Principles of Statistics Hawkes Exam 2 Review

Classify the following as either a discrete random variable or a continuous random variable. The temperature in Kelvin on the planet Jupiter.

Discrete

Decide if the following statement is true or false

It is possible to have a variance of −20 for some data set.

An experiment consists of tossing a coin and rolling a six-sided die simultaneously. Step 2 of 2: What is the probability of getting a tail on the coin and at least a 22 on the die? Round your answer to four decimal places, if necessary

0.4167

Classify the following as either a discrete random variable or a continuous random variable. The populations of countries that belong to the United Nations.

Discrete

The number of hours per week that the television is turned on is determined for each family in a sample. The mean of the data is 30 hours and the median is 26.2 hours. Twenty-four of the families in the sample turned on the television for 15 hours or less for the week. The 11th percentile of the data is 15 hours. Step 5 of 5: Based on the given information, determine if the following statement is true or false. The first quartile is less than 15 hours

False

The number of hours per week that the television is turned on is determined for each family in a sample. The mean of the data is 30 hours and the median is 26.2 hours. Twenty-four of the families in the sample turned on the television for 15 hours or less for the week. The 11th percentile of the data is 15 hours. Step 3 of 5: Based on the given information, determine if the following statement is true or false. Approximately 109 families turned on their televisions for less than 26.2 hours

True

Calculate the interquartile range of the given data. 24,6,35,20,26,46,21,39,51,6,38,32,15,30,22 formula lQR=data set total(pecentage/100)

formula l=n(p/100)=15(75/100)=11.25 (Q3=38) and l=n(p/100)=15(25/100)=3.75 (Q1=20) Q3-Q1 = 38-20 =18

Find the expected value E(X)E(X). Round your answer to one decimal place. x −4, −3, −2, −1, 0 P(X=x)0.3, 0.1, 0.1, 0.2, 0.3

−1.9

Step 2 of 5: Find the variance. Round your answer to one decimal place. x −4, −3, −2, −1, 0 P(X=x)0.3, 0.1, 0.1, 0.2, 0.3

2.7

The number of hours per week that the television is turned on is determined for each family in a sample. The mean of the data is 30 hours and the median is 26.2 hours. Twenty-four of the families in the sample turned on the television for 15 hours or less for the week. The 11th percentile of the data is 15 hours. Step 4 of 5: What is the value of the 50th percentile?

26.2

Consider the following sets of sample data: A: 431431, 447447, 306306, 413413, 315315, 432432, 312312, 387387, 295295, 327327, 323323, 296296, 441441, 312312 B: $1.35$⁢1.35, $1.82$⁢1.82, $1.82$⁢1.82, $2.72$⁢2.72, $1.07$⁢1.07, $1.86$⁢1.86, $2.71$⁢2.71, $2.61$⁢2.61, $1.13$⁢1.13, $1.20$⁢1.20, $1.41$⁢1.41 Step 1 of 2: For each of the above sets of sample data, calculate the coefficient of variation, CV. Round to one decimal place.

CV for Data Set A: 16.9% CV for Data Set B: 35.5%

Consider the following sets of sample data: A: 431431, 447447, 306306, 413413, 315315, 432432, 312312, 387387, 295295, 327327, 323323, 296296, 441441, 312312 B: $1.35$⁢1.35, $1.82$⁢1.82, $1.82$⁢1.82, $2.72$⁢2.72, $1.07$⁢1.07, $1.86$⁢1.86, $2.71$⁢2.71, $2.61$⁢2.61, $1.13$⁢1.13, $1.20$⁢1.20, $1.41$⁢1.41 Step 2 of 2: Which of the above sets of sample data has the larger spread?

Data Set B

The number of hours per week that the television is turned on is determined for each family in a sample. The mean of the data is 30 hours and the median is 26.2 hours. Twenty-four of the families in the sample turned on the television for 15 hours or less for the week. The 11th percentile of the data is 15 hours. Step 1 of 5: Based on the given information, determine if the following statement is true or false. The 54th percentile is greater than or equal to 25 hours.

True??My answer was False but Hawkes marked it incorrect. However their site states : The median is the 50th percentile. And the problem states that the median is 26.6 hours. Since 54th percentile ≥ 50th percentile (by the definition of a percentile), 54th percentile ≥26.6 It is clear that the 54th percentile is greater than or equal to 26.6 hours and hence the given statement is false.

Assume the random variable X has a binomial distribution with the given probability of obtaining a success. Find the following probability, given the number of trials and the probability of obtaining a success. Round your answer to four decimal places. P(X≤1), n=5, p=0.4

0.337

Assume the random variable X has a binomial distribution with the given probability of obtaining a success. Find the following probability, given the number of trials and the probability of obtaining a success. Round your answer to four decimal places. P(X<3), n=4, p=0.6

0.5248

Step 3 of 5: Find the standard deviation. Round your answer to one decimal place. x −4, −3, −2, −1, 0 P(X=x)0.3, 0.1, 0.1, 0.2, 0.3

1.6 - Square the variance

The number of hours per week that the television is turned on is determined for each family in a sample. The mean of the data is 30 hours and the median is 26.2hours. Twenty-four of the families in the sample turned on the television for 15 hours or less for the week. The 11th percentile of the data is 15 hours. Step 2 of 5: Approximately how many families are in the sample? Round your answer to the nearest integer.

218 - From the data given, we know the 11th percentile corresponds to 15 hours of television watching. Thus, x=15 hours percentile of 15 hours =11, and the number of data values less than or equal to 15 hours =24. Therefore, 15/11*100≈218