Question

Reserve Problems Chapter 8 Section 2 Problem 2

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During the nutrition research, the amount of consumed kilocalories per day was measured for 18 people – 10 women and 8 men. Results are as follows:

Women: 1962, 1842, 1588, 1911, 1779, 1603, 1758, 1771, 1874, 1974;

Men: 2097, 2560, 2328, 2399, 2420, 2292, 2263, 2047.

Calculate a 90% confidence interval on the mean for women and men separately. Assume distribution to be normal.
Round your answers to the nearest integer (e.g. 9876).

Women:		Enter your answer; Women: confidence interval, lower bound ≤μ≤ Enter your answer; Women: confidence interval, upper bound
Men:		Enter your answer; Men: confidence interval, lower bound ≤μ≤ Enter your answer; Men: confidence interval, upper bound

Answer 1

for women":

sample mean         x=	1806.200
sample size             n=	10
sample std deviation s=	134.36

std error sx=s/√n=

42.4913

for 90% CI; and 9 df, critical t=		1.8330
margin of error E=t*std error                            =		77.8865
lower bound=sample mean-E =		1728
Upper bound=sample mean+E=		1884

for men:

sample mean         x=	2300.750
sample size             n=	8
sample std deviation s=	168.706
std error sx=s/√n=	59.6465

for 90% CI; and 7 df, critical t=		1.8950
margin of error E=t*std error                            =		113.0301
lower bound=sample mean-E =		2188
Upper bound=sample mean+E=		2414