Problem Set 8
7.12
a. There is somewhat positive and possibly linear relationship, but there are some observation in
the right corner with high height which have small volume.
b. There is positive and linear relationship
c. I prefer to use diameter, becau
Problem set 7
5.26
No, it isnt. First of all, the sample sizes are large. It contains all of the
best actor and best actress winners from 1929 to 2012, so it isnt 10% of
all population. Also, the sample isnt random. Finally, the sample are
very strongly s
Problem Set 6
5.5
95% confidence interval: (18.985, 21.015) = mean t*SE mean = 20
t(35) = 2.03 SE = 0.5
SE = s/n s = 0.5*6 = 3
5.8
a. Yes, the sample is random and less than 10% of users. The sample is small, and we need to use tdistribution. For this siz
Problem Set 5
4.8
99% confidence interval: 52%2.33*2.4%=(46.408%, 57.592%)
We are 99% confident that the fraction of U.S. adult Twitter users who get some news on Twitter
is between 46.408% and 57.592%.
4.10
a. False. We could use 95% confidence interval
Problem Set 4
3.2
a. 87.08%
b. 57.14%
c. 0.02%
d. 38.3%
3.4
b. Leo: Z=(4948-4313)/583=1.09=86.21%
Mary: Z=(5513-5261)/807=0.31=62.17%
Leo is 1.09 standard deviations above the mean on the finishing time of the men
Mary is 62.17 standard deviation above th
Problem Set 3
1.47
a. Dist 1 has a lower mean than Dist 2 because 13 in Dist 1 <20 in Dist 2. Also, Dist 1 has a
lower standard deviation since 13 is closer from the rest of the data.
b. Dist 1 has higher mean than Dist 2 because -20 > -40, and Dist 1 has
Problem set 2
1.2
a. 77.65% of patients in the treatment group experienced a significant improvement in
symptoms.
80.25% of patients in the control group.
b. The symptomatic treatment appears to be more effective for sinusitis.
c. There is a 2.6% differen