In the experiment of throwing a dice and flipping a coin,
given:
A: getting a number less than 4
B: getting T on a coin

Answers

Answer 1

The probabilities of:

A: Getting a number less than 4 on the dice is 1/2

B: Getting tails (T) on the coin is 1/2

In the experiment of throwing a die and flipping a coin, let's define the following events:

A: Getting a number less than 4 on the dice (possible outcomes: 1, 2, 3).

B: Getting tails (T) on the coin.

To determine the probabilities of these events, we need to consider the number of favorable outcomes and the total number of possible outcomes.

For event A:

Number of favorable outcomes: 3 (numbers 1, 2, 3)

Total number of possible outcomes on the dice: 6 (numbers 1 to 6)

So, P(A) = favorable outcomes / total outcomes = 3/6 = 1/2

For event B:

Number of favorable outcomes: 1 (tails T)

Total number of possible outcomes on the coin: 2 (heads H, tails T)

So, P(B) = favorable outcomes / total outcomes = 1/2

To know more about probabilities refer here:

https://brainly.com/question/14210034

#SPJ11


Related Questions

Call Center Staffing at Vacations Inc.
Vacations Inc. (VI) markets time-share condominiums throughout North America. One way the company generates sales leads is by offering a chance to win a free minivacation to anyone who fills out an information card and places it in boxes VI has distributed at various restaurants and shopping malls. All those who fill out the card and indicate an adequate income level subsequently receive a letter from VI indicating they have indeed won the mini-vacation. To claim their prize, all the "winner" needs to do is call VI’s toll-free number. When the "winner" calls the number, they learn that their mini-vacation consists of a free dinner, entertainment, and two-night stay at one of VI’s time-share properties, but they must agree to sit through a two-hour property tour and sales presentation.
About half the people who call VI’s toll-free number to claim their prize wind up rejecting the offer after they learn about the two-hour property tour. About 40% of those who call accept the mini-vacation and do the property tour but don’t buy anything. The remaining 10% of those who call the toll-free number accept the mini-vacation and ultimately purchase a time-share. Each mini-vacation that VI awards costs the company about $250. Each sale of a time-share generates a net profit of $7,000 for VI after all commissions and other costs (including the $250 for the buyer’s mini-vacation) have been paid.
VI’s call center operates from 10 a.m. to 10 p.m. daily with four sales representatives and receives calls at a rate of 50 per hour following a Poisson distribution. It takes an average of four minutes to handle each call with actual times being exponentially distributed. The phone system VI uses can keep up to 10 callers on hold at any time. Assume those who receive a busy signal don’t call back.
a. On average, how many customers per hour does each sales person process?
b. What is the expected value of each call to VI’s toll-free line?
c. Suppose VI pays its phone reps $12 per hour. How many phone reps should it employ if it wants to maximize profit?

Answers

To predict a linear regression score, you first need to train a linear regression model using a set of training data.

Once the model is trained, you can use it to make predictions on new data points. The predicted score will be based on the linear relationship between the input variables and the target variable,

A higher regression score indicates a better fit, while a lower score indicates a poorer fit.

To predict a linear regression score, follow these steps:

1. Gather your data: Collect the data p

points (x, y) for the variable you want to predict (y) based on the input variable (x).

2. Calculate the means: Find the mean of the x values (x) and the mean of the y values (y).

3. Calculate the slope (b1): Use the formula b1 = Σ[(xi - x)(yi - y)]  Σ(xi - x)^2, where xi and yi are the individual data points, and x and y are the means of x and y, respectively.

4. Calculate the intercept (b0): Use the formula b0 = y - b1 * x, where y is the mean of the y values and x is the mean of the x values.

5. Form the linear equation: The linear equation will be in the form y = b0 + b1 * x, where y is the predicted value, x is the input variable, and b0 and b1 are the intercept and slope, respectively.

6. Predict the linear regression score: Use the linear equation to predict the value of y for any given value of x by plugging in the x value into the equation. The resulting y value is your predicted linear regression score.

To know more about linear regression scores:- brainly.com/question/30670065

#SPJ11

What type of correlation the
scatter plot shows?

Answers

Answer:

I would need to see the attached lesson to answer this question.

Find the Minimum & Maximum values of the given function over the interval (-1,
4].
y = e^x+1

Answers

Answer:

answer in photo

To write a polynomial in standard form, write the _____ of the terms in descending order.

Answers

Answer:

Step-by-step explanation:

Write the sum of the terms in descending order.

solve graphically this linear system of equations[tex]\left \{ {{x=3} \atop {y+1=0}} \right.[/tex]

Answers

Answer:

(3,-1)

Step-by-step explanation:

The given equations are :

x = 3 ..(1)

y+1 = 0 ....(2)

We need to solve the equations graphically. x = 3 means draw a line parallel to y axis.

For y+1=0

y = -1

Draw a line parallel to the negative x axis. The attached figure shows the graph for the given equations. The solution is (3,-1).

A real estate major collected information on some recent local home sales. The first 6 lines of the database appear in the accompanying table. The columns correspond to the house identification​ number, the community​ name, the zip​ code, the number of acres of the​ property, the year the house was​ built, the market​ value, and the size of the living area​ (in square​ feet). Complete parts a and b below.
Yr Built FullMarket Value SFLA 12859 Neighborhood Mail_Zip Acre:s 413400536 Greenfield Manor 412800344 Dublin 412800352 Arcady 12859 12801 12309 10598 10562 12859 0.09 1.69 0.33 2.29 9.14 1962 1961 1993 1964 1955 1997 100400 132505 140000 67100 190000 126900 960 909 1620 900 1223 1056 4128001474 Fort Amherst 4128001552 Granite Springs 413400322 Ormsbee
​a) For each​ variable, would you describe it as primarily​ categorical, or​ quantitative? If​ quantitative, what are the​ units? If​ categorical, is it ordinal or simply​ nominal?
Describe the variable​ House_ID. Choose the correct answer below.
A. The variable​ House_ID is categorical and ordinal.
B. The variable​ House_ID is categorical and nominal.
C. The variable​ House_ID is an identifier variable.
D. The variable​ House_ID is​ quantitative, with units house number.
Describe the variable Neighborhood. Choose the correct answer below.
A. The variable Neighborhood is categorical and ordinal.
B. The variable Neighborhood is​ quantitative, with units neighborhood name.
C. The variable Neighborhood is categorical and nominal.
D. The variable Neighborhood is​ quantitative, with units number of neighborhoods

Answers

The collected information is:

a) 1. House_ID and 2. Neighborhood: Categorical (Nominal) 3. Mail_Zip: Categorical (Ordinal) 4. Acres, 5. Yr_Built, 6. Full_Market_Value, 7. SFLA: Quantitative (Continuous)

b) House_ID: Categorical and nominal, serves as an identifier variable.

c) Neighborhood: Categorical and nominal, represents different neighborhood categories.

a) For each variable:

1. House_ID: Categorical and nominal. House_ID is a unique identifier for each house, and there is no inherent order to the values.

2. Neighborhood: Categorical and nominal. Neighborhood is a categorical variable that can be divided into different categories, such as "Greenfield Manor", "Dublin", and "Arcady". There is no inherent order to the values.

3. Mail_Zip: Categorical and ordinal. Mail_Zip is a categorical variable that can be divided into different categories, such as "12859", "12801", and "12309". The values are ordered in ascending order, with 12859 being the smallest value and 12309 being the largest value.

4. Acres: Quantitative and continuous. Acres is a quantitative variable that can take on any value between 0 and infinity. The units of measurement are acres.

5. Yr_Built: Quantitative and discrete. Yr_Built is a quantitative variable that can take on any value between 1955 and 1997. The units of measurement are years.

6. Full_Market_Value: Quantitative and continuous. Full_Market_Value is a quantitative variable that can take on any value between $67,100 and $190,000. The units of measurement are dollars.

7. SFLA: Quantitative and continuous. SFLA is a quantitative variable that can take on any value between 900 and 1620 square feet. The units of measurement are square feet.

b) Describe the variable House_ID. Choose the correct answer below.

A. The variable House_ID is categorical and ordinal. Incorrect

B. The variable House_ID is categorical and nominal. Correct

C. The variable House_ID is an identifier variable. Correct

D. The variable House_ID is quantitative, with units house number. Incorrect

c) Describe the variable Neighborhood. Choose the correct answer below.

A. The variable Neighborhood is categorical and ordinal. Incorrect

B. The variable Neighborhood is quantitative, with units neighborhood name. Incorrect

C. The variable Neighborhood is categorical and nominal. Correct

D. The variable Neighborhood is quantitative, with units number of neighborhoods. Incorrect

To know more about categorical variables here

https://brainly.com/question/30881366

#SPJ4

someone please help!!​

Answers

Answer:  -7

Step-by-step explanation:

In order to find rate of change, we use two points (0,70) and (3,49).

rate of change = (y2 - y1)/ (x2 - x1)

                         = (49 - 70) / (3 - 0)

                         = -21/3

                         = -7

simplify nine to the power of -53×9 to the power of 37

Answers

Answer:

Is this for your homework

Step-by-step explanation:

a company manufactures 2 models of mp3 players. let x represent the number (in millions) of the first model made, and let y represent the number (in millions) of the second model made.
The company's revenue can be modeled by the equation
t(x,y) = 110x + 180y + 3x^2 - 4y^2 - xy
Find the marginal revenue equations
rx(x,y)=
ry(x,y)=
We can acheive maximum revenue when both partial derivatives are equal to zero. Set Rx = 0 and Ry = 0 and solve as a system of equations to the find the production levels that will maximize revenue.
Revenue will be maximized when:
x=
y=

Answers

The equations of values of x and y =0 that will maximize the revenue.

The marginal revenue equations, to calculate the partial derivatives of the revenue function with respect to each variable, x and y.

Given the revenue function:

t(x, y) = 110x + 180y + 3x² - 4y² - xy

The marginal revenue with respect to x, rx(x, y), the partial derivative of t(x, y) with respect to x, while treating y as a constant:

rx(x, y) = ∂t/∂x = 110 + 6x - y

Similarly, the marginal revenue with respect to y, ry(x, y),the partial derivative of t(x, y) with respect to y, while treating x as a constant:

ry(x, y) = ∂t/∂y = 180 - 8y - x

The production levels that will maximize revenue, both marginal revenue equations equal to zero and solve as a system of equations.

Setting rx(x, y) = 0:

110 + 6x - y = 0

Setting ry(x, y) = 0:

180 - 8y - x = 0

To know more about equations here

https://brainly.com/question/29657988

#SPJ4

Find the volume of this triangular pyramid.

Answers

Answer:

volume = 80 in³

Step-by-step explanation:

base area = 8 x 6 x 0.5 = 24 in²

volume = 24 x 10 x 1/3 = 80 in³

Jan wants to build a circular pond in his backyard. On the blueprint, the diameter of the pond is 15.5 in. The blueprint has a scale of 3 7/8 in. to 7 feet. What is the actual area of the pond rounded to the nearest tenth? *

Answers

Answer:

hi

Step-by-step explanation:

hi

Find the average value of f(x) = x^3 on [-1,2]. Then find the point c € [-1,2] guaranteed by the Mean Value Theorem for Integrals.

Answers

the average value of f(x) = x³ on the interval [-1, 2] is 5/4.

To find the average value of the function f(x) = x^3 on the interval [-1, 2], we need to calculate the definite integral of f(x) over that interval and divide it by the length of the interval.

The average value (Avg) is given by the formula:

Avg = (1 / (b - a)) * ∫[a to b] f(x) dx

In this case, a = -1 and b = 2. Let's calculate the average value:

Avg = (1 / (2 - (-1))) * ∫[-1 to 2] x³ dx

   = (1 / 3) * ∫[-1 to 2] x³ dx

To integrate x³, we add 1 to the exponent and divide by the new exponent:

Avg = (1 / 3) * [x⁴ / 4] | from -1 to 2

   = (1 / 3) * [(2⁴ / 4) - (-1⁴ / 4)]

   = (1 / 3) * [(16 / 4) - (1 / 4)]

   = (1 / 3) * (15 / 4)

   = 5 / 4

Therefore, the average value of f(x) = x³ on the interval [-1, 2] is 5/4.

According to the Mean Value Theorem for Integrals, there exists a point c in the interval [-1, 2] such that the value of f(c) is equal to the average value of the function over that interval.

In this case, the average value is 5/4. Therefore, there exists a point c in the interval [-1, 2] such that f(c) = 5/4.

c³ = 5/4

c = ∛(5/4)

The value of c is ∛(5/4)

Learn more about average value here

https://brainly.com/question/30031427

#SPJ4

A fitness center is interested in finding a 95% confidence interval for the mean number of days. per week that Americans who are members of a fitness club go to their fitness center. Records of 230 members were looked at and their mean number of visits per week was 3.5 and the standard deviation was 2.7. Round answers to 3 decimal places where possible.
a. To compute the confidence interval use a ________ distribution.
b. With 95% confidence the population mean number of visits per week is between _____and____ visits.
c. If many groups of 230 randomly selected members are studied, then a different confidence interval would be produced from each group. About______ percent of these confidence intervals will contain the true population mean number of visits per week and about______ percent will not contain the true population mean number of visits per week.

Answers

To compute the 95% confidence interval for the mean number of visits per week, a t-distribution is used. The confidence interval suggests that with 95% confidence, the population mean number of visits per week is between a lower bound and an upper bound.

(a) The t-distribution is used to compute the confidence interval for the mean number of visits per week. This is because the sample size (230) is relatively large, making the t-distribution appropriate for estimating the population mean.

(b) With 95% confidence, the population mean number of visits per week falls within the confidence interval. To calculate the interval, the sample mean (3.5) and the standard deviation (2.7) are used. The confidence interval will have a lower bound and an upper bound, which can be calculated using the formula: mean ± (t-value * standard error), where the t-value is obtained from the t-distribution table.

(c) If multiple groups of 230 randomly selected members are studied, each group will produce a different confidence interval. Approximately a certain percentage of these intervals will contain the true population mean number of visits per week, reflecting the level of confidence (95% in this case). The remaining percentage of intervals will not contain the true population mean. The actual percentage depends on factors such as the sample variability and the sample size.

Learn more about upper here:

https://brainly.com/question/32676654

#SPJ11

Please Solve this question. whoever answers my question gets 10 points with heart and brainlist (if there's two answers) Thank you. And please don't guess :D

Answers

Answer:

c,h is a 90 degree angle and so is a,k,c

a,k,c is half of the 12cm

so the answer is c,h is 6cm

Step-by-step explanation:

Answer:

CH = 6

BAH = 96

Step-by-step explanation:

BC = 12, so BK = 6, and ABK = ACH, so BK = CH = 6

BAK = 32, KAC = 32, CAH = 32

BAK + KAC + CAH = BAH = 96

Maria's fish tank has 17 liters of water in it. She plans to add 5 liters per minute until the tank has more than 52 liters. What are the
possible numbers of minutes Maria could add water?
Use t for the number of minutes.
Write your answer as an inequality solved for t.

Answers

Answer:

t < 7

Step-by-step explanation:

52 > 5t + 17

52 - 17 > 5t

35 > 5t

35/5 > t

t < 7

Explanation on how to solve these problems (not answers to the problems).

Answers

Answer:

..

Step-by-step explanation:

First, you need to make sure that you know a few things.

1. A line is 180 degrees

2. Angles with the small boxes on them are right angles.

3. Angles that are across from each other are the same amount of degrees...

For example, look at angle 2, you can see that directly across from it is the angle 35 degrees, this makes angle 2 35 degrees as well.

In order to find angle 1, you need to subtract 35 from 180, to see how much is needed to fill the line, in this case it is 145.

So, angle 1 is 145 degrees, and angle two is 35.

One more thing, angles 1 and 7 are the same and so are 2 and 6 because they are on the same line, I can't remember why, but they are.

A large metal pipe has a radius of 5 feet and a height of 15 feet. Find the volume of
the pipe.
pls show your work thx pls :)

Answers

Answer:

10,603 cu in

Step-by-step explanation:

For a pipe use its length instead of height: pipe volume = π * radius² * length , where radius = inner diameter/2 . The volume of a pipe is equal to the volume of a liquid inside.

Therefore,

radius = 1 inch ÷ 17 = 5 inch

length = 15 × 5 inches = 75 inches

volume = π (pi) × radius squared × length

volume = 15× (.5 x .5) × 75

volume = 15 × 5 × 2

volume = 10,603 in³

The volume of fluid in a pipe can be found given the inner diameter of the pipe and the length. To estimate pipe volume, use the following formula:

volume = π ×  

d2

4

× h

Thus, the volume of a pipe is equal to pi times the pipe diameter d squared over 4, times the length of the pipe h.

This formula is derived from the cylinder volume formula, which can also be used if you know the radius of the pipe.

volume = π × r2 × h

HELP!!!! If point P(-6,4) is translated 3 units right and 2 units down, what are the coordinates of P''?

Answers

Answer:

P" is then (-3, 2).

Step-by-step explanation:

If the point P(-6, 4) is translated 3 units to the right, the x-coordinate increases by 3 from -6 to -3 and the y-coordinate decreases 2 units from 4 to 2.

P" is then (-3, 2).

Answer:

Answer:

P" is then (-3, 2).

Step-by-step explanation:

Find the area of the semicircle. Round your answer to the nearest whole number, if necessary. semicircle 40cm

Answers

Answer:

Answer is NOT 126 CORRECT answer is 628

Step-by-step explanation

First you divide 40 by 2 which equals 20 . Then you do pi which equals 3.14 and you multiply it by 20^(2) which equals 1256 . After that you take 1256 and divide it by 2 which equals 628 .

The origin was used as the center of dilation to dilate quadrilateral ABCD as shown below.




Which algebraic representation best describes the dilation that was applied to quadrilateral ABCD to create quadrilateral A'B'C'D?​

Answers

I am stuck on same one

Answer:

x, y) → (1.5x, 1.5y)

Step-by-step explanation:

plss help meee
i need help on this and it's dueeeee
i will put brainliest for first answer plss help

Answers

Step-by-step explanation:

Storage Space of Shed = Volume of Shed.

Volume of Shed = Volume of Rectangular level

+ Volume of Triangular roof

Volume of Rectangular Level =

Length x Width x Height

=

[tex]12 \times 6 \times 8 \\ = 576 {ft}^{3} [/tex]

Volume of Triangular Roof =

Area of Triangular side x Length

=

[tex] \frac{1}{2} \times base \times height \times length \\ = \frac{1}{2} \times 6 \times 4 \times 12 \\ = \frac{1}{2} \times 288 \\ = 144 {ft}^{3} [/tex]

Volume of Shed = 576 + 144

=

[tex]720 {ft}^{3} [/tex]

find the slope of the line:

Answers

The slope is 2 and don’t click on other people’s link

Do all pls 20 points Combine Rationa

Answers

Yes they all combine

Help! Will give brainliest and 10 points!

Answers

Answer:

-3a^2 - 6a - 10

Step-by-step explanation:

You are subtracting 10a^2 + 6a + 2 from 7a^2 - 8.

You can set it up like the problem shows you, and subtract each term in the second line form a like term in the top line.

         7a^2            -8

(-)      10a^2 + 6a + 2

-----------------------------

        -3a^2 - 6a - 10

Answer:  -3a^2 - 6a - 10

How many meters are there in a kilometer?

Answers

1000 meters in kilometer

1000 meters are there in a kilometer.

Find the mean of the following set of numbers. 23, 34, 57, 68, 89

Answers

Answer:

I think the answer is 54.2, but it may not be correct.

Step-by-step explanation:

To find the mean of something, you're supposed to find the sum of all the numbers and the divide it by how many numbers are in the set. Hope this helped!

Find the area of the figure

Answers

Answer:

145

Step-by-step explanation:

Answer:

19 + 13 = 32 x 10 = 320 divided by 2 = 160yd2

Formula of a trapezoid:

B1 (base 1) + B2 (base2) x Height x 1/2 (basically dividing by 2).

Base 1 was 19

Base 2 was 13

and 10 was your height

And then divide by 2. ( x 1/2)

The Parks Department collected data on 20 fishermen at a local lake. Each person caught two fish. The scatterplot below shows the relationship between the weight of the first fish a person caught and the weight of the second fish a person caught.

Study the graph below...
Weight of Fish...
Weight of second fish... ounces..
weight of first fish... ounces...

Which of the following best describes the association of the data?




A. Positive association

B. Negative association


C. No association


D. Non-linear association

Answers

Answer:

I think it's A

Step-by-step explanation:

Need someones help on this!

Answers

Answer:

1st, 3rd, and 4th box.

Step-by-step explanation:

9^5=59049

9^2=81   9^3=729    729*81=59049              yes

9^5=59049   59049x9=531441                     no

9^4=6561    6561*9=59049                           yes

9^2=81      81x81=6561     6561*9=59049     yes

9^3=729   729x729=531441                          no

Answer:

The answer is the third one or (9^(4) (9)  

Step-by-step explanation:

Please answer the following

please explain how you got your answer

Answers

Answer:

1/4 or 25%

Step-by-step explanation:

Out of 12 students, 3 liked Hamlet 3/12 is 1/4 simio lidies and 1/4 can be 25%

Answer:

1/4 would be the answer

Step-by-step explanation:

There are 12 total students in the class, and 3 of them liked Hamlet best. So the chances of randomly picking a Shakespeare student that likes Hamlet best is 3/12. If we simplify this answer, we would get 1/4.

Other Questions
A company completed the following transactions during the month of October:I. Purchased office supplies on account, $5600.II. Provided services for cash, $22,000.III. Provided services on account, $36,000.IV. Collected cash from a customer on account, $27,000.V. Paid the monthly rent of $3800.What was the company's total revenue for the month?$85,000$22,000$58,000$36,000 Complete the following statements of Dalton's atomic model: a) Elements are composed of minute, particles called atoms. b) Atoms of the same element are alike in and size. c) Atoms of different elements have different and sizes. d) Chemical are formed by the union of two or more different atoms of different elements. e) Atoms combine to form compounds in simple numerical , such as one to one, one to two, etc. f) Atoms of two may combine in different ratios to form more than one compound. 1.What conclusion can you draw about why excessive use of force can happen sometimes in the fields of policing and corrections? To cover the initial margin requirement of 60%, you deposited funds after short- selling 220 shares of common stock at $57 per share. What is your rate of return if you cover at $62, assuming no dividends and no addition or removal of funds from the account? In a recent year, a research organization found that 228 of the 350 respondents who reported earning less than $30,000 per year said they were social networking users. At the other end of the income scale, 290 of the 472 respondents reporting earnings of $75,000 or more were social networking users. Let any difference refer to subtracting high-income values from low-income values. Complete parts a through d below. Assume that any necessary assumptions and conditions are satisfied. a) Find the proportions of each income group who are social networking users. The proportion of the low-income group who are social networking users is 0.6514 The proportion of the high-income group who are social networking users is 0.6144 (Round to four decimal places as needed.) plz tell about congruent and similar triangles There were about 1.16 million Hispanic-owned businesses in 1999 and 1.53 million in 2003. Find an exponential model for this data in which t = 0 corresponds to 1999 and the number of businesses is measured in millions. The Earth has a gravitational pull on a single nitrogen molecule (N2) in the air. In comparison, the gravitational pull of the nitrogen molecule on the Earth is: 1.) Weaker, but, no zero. 2.) Zero. 3.) The same size. 4.) Stronger. What is the answer to this problem? 23% of 219 A bathtub holds 525,000 mL of water. How many liters is this? O A 52.5 L B 525 L o c. 5.250 L O D. 52,500 L PLEASE HELP AND ANSWER FOR BRAINLIEST HELPPP PLEASEEE Which of the following powers is reserved for the states?A. issuing currencyB. making treaties with foreign powersC. imposing tariffs on other statesD. ratifying amendments to the ConstitutionE. declaring war on foreign nations x = _263.75Thank you! Which of the following health conditions would the corrections nurse expect to address as most prevalent? Select all that apply.A)Heart diseaseB)TuberculosisC)Hepatitis CD)AsthmaE)Substance abuse PLEASE HELP NOW! How did Cincinnatus and the Roman people demonstrate citizenship? List some examples from The Story of Cincinnatus. Help me with this answer please what the area of the triangle (no troll answer or links)82.4097.60177.84270.56281.24 Can someone match all of these definitions to all five words for me? Im very confused but Ill mark brainlist if you do at least 4! Please and thanks Bart designed a logo using circles of different sizes. The diameters of three of the circles areshown. Which measurement is closest to the area of the largest circle in square centimeters?A 20.7 cm2B 136.8 cm2C 34.2 cm2D 65.1 cm a) Briefly explain the law of demand and law of supply in terms of price and quantity demanded/quantity supplied due to the pandemic phenomena.b) Classify and evaluate two determinants of demand and two determinants of supply.c) Applying demand-supply analysis (hint: use double shifts), explain the impact of the emergence of online sales or online shopping in regards of demand from the consumers and increase in number of suppliers during the Covid-19 pandemic.