Business Stats HW 2 (Attempt 1)

Suppose it is known that the mean and standard deviation of the scores on a statistics final are 73.12 and 8.05, respectively. Calculate an interval that is symmetric around the mean such that it contains approximately 95% of scores. Assume that the scores have a normal distribution.

(57.02, 89.22)

Suppose that the mean and standard deviation of the scores on a statistics exam 75.3 and 5.34, respectively, and are approximately normally distributed. Calculate the proportion of scores between 78 and 81.

0.1637

Suppose that the number of gallons of milk sold per day at a local supermarket are normally distributed with mean and standard deviation of 356.5 and 27.73, respectively. What is the probability that on a given day the supermarket will sell between 322 and 354 gallons of milk?

0.2756

Suppose that the mean and standard deviation of the scores on a statistics exam are 79.1 and 6.12, respectively, and are approximately normally distributed. Calculate the proportion of scores between 72 and 83.

0.6150

Surveyors measured the number of cars that go through the intersection of Howard Street and Stadium Drive each hour during the morning commute time. The average number of cars was 1,009.3 with a standard deviation of 15.77. They expect traffic to change in the upcoming semester so 52 is added to every observation in the dataset. What will the new mean be?

1,061.3

Google's stock (GOOG) was tracked for 10 days, showing closing prices of 1,202.11; 1,121.32; 1087.23, 1,130.45; 1095.47; 1,108.16; 1,134.39; 1,129.12; 1,131.26; 1,135. Calculate the mean of the dataset.

1,117.451

Lawmakers are considering a new tax to discourage cigarette consumption and promote healthy lifestyle choices. Taxes on cigarettes prior to this new legislation tended to average $2,494 with a standard deviation of $0.354. To calculate the new cigarette tax, every observation in the dataset is multiplied by 1.068. What will the new mean be?

2.66

The temperature in Grand Haven in August (fahrenheit) for 10 days was 74.6; 83; 80.7; 81.4; 67.5; 75.4; 77.6; 74.1; 80.5; 80.4. Calculate the standard deviation of the dataset.

4.684

Suppose that the middle 95% of monthly food expenditures for a family of four fall between 365.32 and 670.48. Give an approximate estimate of the standard deviation fo the expenditures. Assume the expenditures have a normal distribution.

76.29