QUESTION 1 Use techonology to construct the confidence intervals. Assume the pop

Question

QUESTION 1 Use techonology to construct the confidence intervals. Assume the population of times is normally distributed A research council wants to estimate he mean len h o time in minutes the average U adult spends watchin of 20 U.S. and obtains the following results 15, 18, 17, 20, 24, 12, 9, 15, 14, 25, 8, 6, 10, 14, 16, 20, 27, 10, 9, 13 Find the lower bound (round to 2 decimal places) of the 99% of the confidence interval for the population mean. O 11.34 /s usin digital video r con ers V s each da od termine ses a re arch a esa no sample O 18.86 9.22 O15.1 QUESTION 2 ccer bal manu ac urer wants o estimate he me an crcumferenca o soccer balls within nch. e er n he minum um samp size require o cons uct a % con encante a or e po ulation mean. s un ete pop at standard deviation is 0.25 inch. O 40 41 O 42 O 43

Explanation / Answer

1) mean = 15.1

Standard deviation = 5.73

At 99% cinfidence interval the critical value is Z0.995 = 2.58

Lower bound is

Mean - Z0.995 * SD/sqrt (n)

= 15.1 - 2.58 * 5.73/sqrt(20)

= 15.1 - 3.31

= 11.79

Option-A is the correct answer.

2) margin of error = 0.1

Or, Z0.995 * sd/sqrt (n) = 0.1

Or, 2.58 * 0.25/sqrt(n) = 0.1

Or, sqrt(n) = (2.58 * 0.25)/0.1

Or, sqrt (n) = 6.45

Or, n = 41.6 = 42

Option-C is the correct answer.

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