Circle the correct letter Construct a 97 percent confidence interval around a sa
ID: 3066745 • Letter: C
Question
Circle the correct letter Construct a 97 percent confidence interval around a sample mean of 31.3 taken from a population that is not normally distributed with a standard deviation of 7.6 using a sample of size 40. (for 97 percent C.I., z-2.17) 1. a) (28.70, 33.90) b) (2.17, 4.58) c) (33.90, 66.12) d) (28.22, 34.38) What sample size would be necessary to ensure a margin of error of 5 for a 98 percent confidence interval taken from a population that is not normal, which has a population standard deviation of 15? 2. a) 0.004 b) 49 c) 9 d) 32
Explanation / Answer
Solution1:
n=40
large sample
sample follows normal distribution even when population is not normally distributed.
lower limit=sample mean-z(pop stddev/sqrt(n)
=31.3-2.17(7.6)/sqrt(40)
=28.7
upper limit=31.3+2.17(7.6)/sqrt(40)
=33.9
28.7<mu<33.9
(28.7,33.9)
OPTIONA