statistics 101
lmoueomx
stat_hw.docx1. A survey of Whoville found that 403 out of the 620 homes surveyed had cable television
service (sample1). A survey from Bedrock found that 503 of the 740 homes surveyed had
cable television (sample2). Perform a hypothesis test to determine if the proportion of
homes with cable service in Whoville is lower than the proportion in Bedrock. Calculate the
95% confidence interval for the difference in proportions between Whoville and Bedrock.
Do the test to see if the normal approximation is valid for both samples!
A) (2 points) State the claim and the alternate hypothesis (H1) for p1 ( ≠ p2; < p2; > p2 ).
What type of test used to evaluate the owner’s claim?
B) (4 points) With an = 0.05, is the proportion lower in Whoville?
What is the p-value?
Do you Reject the Null Hypothesis or Not Reject the Null Hypothesis?
State the result (whether the data supports the claim or not).
C) (2 points) What is the 95% confidence interval for the difference in proportion between
Whoville and Bedrock?
For all questions, in addition to your answer, please
write down what you entered into your calculator. Homework Assignment #9 – Intro to Statistics – MTH115 – Spring 2014
Page 2
2. Two groups had their blood pressures measured. Group 1 was a random sample of 50
women from St. Charles with a mean of 92.2 and a standard deviation of 5.6. Group 2 was a
random sample of 50 men from St. Charles with a mean of 94.8 and a standard deviation of
8.2. Do not assume the population standard deviations are the same. Test to see if women
from St. Charles have lower blood pressures than men. Calculate the 90% confidence
interval for the difference in blood pressure between the two groups.
A) (2 points) State the claim and the alternate hypothesis (H1) for µ1: ( ≠ µ2; < µ2; > µ2 )
What type of test used?
(2-SampTTest Pooled, 2-SampTTest Non-Pooled, 2Samp-ZTest, TTest Paired)
B) (4 points) With an = 0.05, do women have lower blood pressure?
What is the p-value?
Do you Reject the Null Hypothesis or Not Reject the Null Hypothesis?
State the result (whether the data supports the claim or not).
C) (2 points) What is the 90% confidence interval for the difference in blood pressure?
Homework Assignment #9 – Intro to Statistics – MTH115 – Spring 2014
3. Using the same sample data from Problem #2, you are told that the population standard
deviation for blood pressure for women from St. Charles is 8.0 and the population standard
deviation for men is 10.5. Using this new information, test to see if women from St. Charles
have a lower mean blood pressure than men. Calculate the 90% confidence interval for the
difference in blood pressure between the two groups.
A) (2 points) State the claim and the alternate hypothesis (H1) for µ1: ( ≠ µ2; < µ2; > µ2 )
What type of test used?
(2-SampTTest Pooled, 2-SampTTest Non-Pooled, 2Samp-ZTest, TTest Paired)
B) (4 points) With an = 0.05, do the women have lower mean blood pressure?
What is the p-value?
Do you Reject the Null Hypothesis or Not Reject the Null Hypothesis?
State the result (whether the data supports the claim or not).
C) (2 points) What is the 90% confidence interval for the difference in blood pressure?
4. In order to determine whether the average age of men and women attending a football game
were significantly different, a survey of 40 men had an average age of 46.6 with a sample
standard deviation of 6.0. A survey of 30 women at the same game had a sample mean of
44.2 and a sample standard deviation of 4.8. Assuming the population standard deviations
for men and women are the same, perform a test to see if there is a difference in the average
age of men and women who attend football games (that is, the ages are not the same).
Calculate the 95% confidence interval for the difference between men and women.
A) (2 points) State the claim and the alternate hypothesis (H1) for µ1: ( ≠ µ2; < µ2; > µ2 )
What type of test used?
(2-SampTTest Pooled, 2-SampTTest Non-Pooled, 2Samp-ZTest, TTest Paired)
B) (4 points) With an = 0.05, are the ages significantly different?
What is the p-value?
Do you Reject the Null Hypothesis or Not Reject the Null Hypothesis?
State the result (whether the data supports the claim or not).
C) (2 points) What is the 95% confidence interval for the difference in age?
Homework Assignment #9 – Intro to Statistics – MTH115 – Spring 2014
5. The table on the right shows the paired measurements of systolic blood
pressure for 25 married couples. Perform a hypothesis test on this data to
determine whether the husbands’ mean blood pressure is more than two
points higher than the wives’. That is, test whether the difference in blood
pressure is greater than 2 points. Don’t worry about outliers.
A) (2 points) State the claim and the alternate hypothesis for the
difference in blood pressure. What type of test used?
(pick from the same options as in Problem 4)
B) (4 points) With an = 0.05, are the husband’s pressures more than
2 points greater? What is the p-value?
Do you Reject or Not Reject the Null Hypothesis?
State the result (whether the data supports the claim or not).
C) (2 points) What is the 95% confidence interval for the difference in
blood pressure between husband and wife?
Husband Wife
111 106
117 113
118 112
117 112
118 117
119 112
114 118
124 114
122 114
121 117
124 120
119 119
121 121
121 122
126 122
128 121
131 126
131 128
131 128
129 127
127 126
134 131
132 127
132 132
135 133
