Lesson exercises 4.1 & 4.2 & 4.3 & 4.6

Suppose that IQ scores have a bell-shaped distribution with a mean of 100 and a standard deviation of 13. Using the empirical rule, what percentage of IQ scores are between 74 and 126?

1 dev = 68% data 2 dev = 95% 3 dev = 99.7% mean = 100 std dev = 13 Find what % btwn 74 & 126 Add & subtract std dev from mean until reach the averages given

Suppose that grade point averages of undergraduate students at one university have a bell-shaped distribution with a mean of 2.54 and a standard deviation of 0.44. Using the empirical rule, what percentage of the students have grade point averages that are between 2.1 and 2.98?

1 dev = 68% data 2 dev = 95% 3 dev = 99.7% mean = 2.54 std dev = 0.44 Find what % btwn 2.1 & 2.98 Add & subtract std dev from mean until reach the averages given

Suppose that shoe sizes of American women have a bell-shaped distribution with a mean of 8.47 and a standard deviation of 1.5. Using the empirical rule, what percentage of American women have shoe sizes that are between 5.47 and 11.47?

1 dev = 68% data 2 dev = 95% 3 dev = 99.7% mean = 8.47 std dev = 1.5 Find what % btwn 5.47 & 11.47 Add & subtract std dev from mean until reach the averages given

Suppose that IQ scores have a bell-shaped distribution with a mean of 95 and a standard deviation of 18. Using the empirical rule, what percentage of IQ scores are between 41 and 149?

1 dev = 68% data 2 dev = 95% 3 dev = 99.7% mean = 95 std dev = 18 Find what % btwn 41 & 149 Add & subtract std dev from mean until reach the averages given

Calculate the z-score of the given x value, x=79.8 mew= x bar = x‾=83.3 s=6.3 Round your answer to two decimal places.

First, remember that the equation we use to calculate a z-score is z= x- x bar/s . Substituting the given values into the equation gives us z=(79.8−83.3) / 6.3≈ −0.56 .

A manufacturer makes bags of popcorn and bags of potato chips. The average weight of a bag of popcorn is supposed to be 3.05 ounces with an allowable deviation of 0.02 ounces. The average weight of a bag of potato chips is supposed to be 5.02 ounces with an allowable deviation of 0.03 ounces. A factory worker randomly selects a bag of popcorn from the assembly line and it has a weight of 3.02 ounces. Then the worker randomly selects a bag of potato chips from the assembly line and it has a weight of 5.05 ounces. Which description closely matches the findings on the assembly line?

Potato = 5.02 - 5.05 = .03 (allowable dev = .03) popcorn = 3.05 -3.02 =.03 (allowable dev = .02) THEREFORE POTATO IN ACCEPTABLE STANDARD AND POPCORN IS NOT

It is possible to have a standard deviation of −19−19 for some data set.

Std Dev are not negative because it is only defining the distance from the mean therefore false

According to a study administered by the National Bureau of Economic Research, half of Americans would struggle to come up with $2000 in the event of a financial emergency. The majority of the 1900 Americans surveyed said they would rely on more than one method to come up with emergency funds if required. In the survey, 433 people said that they "certainly" would not be able to cope with an unexpected $2000 bill if they had to come up with the money in 30 days, and 517 people said they "probably" would not be able to cope. Step 1 of 2 : What percentage of Americans "certainly" would not be able to produce $2000 in the event of an emergency according to the study? Round your answer to one decimal place, if necessary. Step 2 of 2: What percentage of Americans "probably" would not be able to produce $2000

Step 1 433/1900 =0.227894737 = 0.227894737 * 100 = 22.7% Step 2 517/1900 = 0.272105263 =27.2%

Three potential employees took an aptitude test. Each person took a different version of the test. The scores are reported below. Reyna got a score of 75.3 ; this version has a mean of 69.3 and a standard deviation of 12 . Kaitlyn got a score of 228.4 ; this version has a mean of 206 and a standard deviation of 28 . Cade got a score of 7.88 ; this version has a mean of 7.2 and a standard deviation of 0.4 . If the company has only one position to fill and prefers to fill it with the applicant who performed best on the aptitude test, which of the applicants should be offered the job?

calculate z-score of each of the employees and then whoever recieved the highest score is the most qualified in this case reyna got .5 kaitlyn got .8 cade got 1.7 THEREFORE CADE IS MOST QUALIFIED

A study conducted at Virginia Commonwealth University in Richmond indicates that many older individuals can shed insomnia through psychological training. A total of 77 insomnia sufferers averaging age 67 years old completed eight weekly sessions of cognitive-behavior therapy. After the therapy, 30 participants enjoyed a substantially better night's sleep. Calculate the sample proportion of insomnia sufferers who did not enjoy a better night's sleep after the therapy. Round your answer to three decimal places, if necessary.

p= (X/n) X = 77-30 = 47 n= 77 p=(47/77) = 0.61038961 This time do not round the question is asking for decimal value not percentage

Select the word or phrase that will correctly complete the statement. A/An measures the number of standard deviations that a particular value is away from the mean.

z score

Select the word or phrase that will correctly complete the statement. A/An is calculated by dividing the difference between a data value and the mean by the standard deviation.

z-score