Business Stats HW 2 (Attempt 2)

Suppose that the average and standard deviation of the shelf life in years for certain kinds of batteries are 14.37 and 2.29, respectively. Calculate an interval that is symmetric around the mean such that it contains approximately 68% of battery shelf lives. Assume that the life has a normal distribution.

(12.08, 16.66)

Suppose that the average and standard deviation of the fine for speeding on a particular highway are 101.01 and 17.49, respectively. Calculate an interval that is symmetric around the mean such that it contains approximately 68% of fines. Assume that the fine amount has a normal distribution.

(83.52, 118.5)

If the scores per round of golfers on the PGA tour are approximately normally distributed with mean 64 and standard deviation 1.29, what is the probability that a randomly chosen golfer's score is between 62 and 63 strokes?

0.1586

The stock price for International Business Machines (IBM) historically has followed an approximately normal distribution (when adjusting for inflation) with a mean of $166.305 and standard deviation of $4.2216. What is the probability that on a selected day the stock price is below $162.5?

0.1837

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 332 and 354 gallons of milk?

0.2756

Google's stock (GOOG) was tracked for 10 days, showing closing prices of 1,117.95; 1,128.94; 1,101.23; 1,122.73; 1,126.18; 1,113.77; 1,101.17; 1,118.64; 1,117.85; 1,116.05. Calculate the mean of the dataset.

1,116.451

Total enrollment in the Kalamazoo Public Schools have a mean and standard deviation of 11,485.2 and 19.2, respectively. The district expects growth in the next five years, so every observation in the dataset is multiplied by 1.2. What will the new mean be?

13,782.24

The scores of 10 golfers were 73; 78; 71; 80; 75; 68; 66; 72; 78; 77. Calculate the standard deviation of the dataset.

4.61

Suppose that a police officer measured the speed of cars on a highway for an hour. The average speed of the cars was 72 and the standard deviation was 4.07. However, since the radar gun was biased, 3.6 is added to every observation in the dataset. What will the new mean be?

75.6