Problem 1.
WEE-426-25: Women's Weights (Lesson 17)
Summary of Weights
No Selector
Count: 40
Mean: 136.875
Median: 136.5
MidRange: 141
StdDev: 12.7685
Range: 52
IntQRange: 19
The U.S. National Center for Health Statistics estimates mean
weights of Americans by age, height, and sex and publishes the
results in Vital and Health Statistics.
40
U.S. women, 5 ft 4 in.
tall and age 18-24, are randomly selected. Their weights, in
pounds, are recorded in Data Desk.
Assume that the population standard deviation of all such weights
is 10.0 lb
.
d. What is the sample size?
Answer:
n = 40
e. To construct a confidence interval, which procedure is more
appropriate, z-interval or t-interval? Explain briefly.
Answer:
z-Interval, coz it’s more appropriate for larger samle
size.
z-Interval for Individual µ’s
No Selector
Sigma =
10,00
Individual Confidence 95,00%
Bounds:
Lower Bound < µ < Upper Bound
With 95,00% Confidence, 133,77602 < µ(Weights) < 139,97398
f. Construct 95% and 99% confidence intervals for the mean weight
of all U.S. women 5 ft 4 in. tall and in the age group 18-24
years.
Answer
:
z-Interval for Individual µ’s
No Selector
Sigma =
10,00
Individual Confidence 99,00%
Bounds:
Lower Bound < µ < Upper Bound
With 99,00% Confidence, 132,80226 < µ(Weights) < 140,94774
g. Interpret your answers in Part (c).
Answer:
We are 99 %
confident that estimated weight for Forty U.S. women, 5 ft 4
in. tall and age 18-24
h. Which confidence interval is wider, 95% or 99%?
Answer:
99% -
is wider.
i. What is the margin of error for each confidence interval?