# 1. The United States Forest Service is interested in determining the percentage of acreage in Yosemite that would fall below a certain threshold of trees per acre so that they might estimate how many...

1. The United States Forest Service is interested in determining the percentage of acreage in Yosemite
that would fall below a certain threshold of trees per acre so that they might estimate how many new
trees to buy in order to make sure all of Yosemite is considered well-forested. The distribution of trees
per acre in Yosemite is approximately Normal with a mean of XXXXXXXXXXtrees per acre and a standard
deviation of 3 trees per acre. A tree per acre count below XXXXXXXXXXis considered understocked for a forest.
Roughly what percentage of acres in Yosemite would you say is "understocked"?
a. 95%
. 0.15%
c. 0.3%
d. 5%
e. 2.3%

7. The histogram below shows the distribution of homework grades across all STAT-303 sections.

Suppose the mean of this distribution is 62, with a standard deviation of XXXXXXXXXXWhat is the probability that a
andomly-selected student scored higher than a 60?
a. 0.44
. The probability cannot be calculated because the distribution is not Normal; it is skewed left
c XXXXXXXXXX
d XXXXXXXXXX
e. The probability cannot be calculated because the distribution is not Normal; it is skewed right

8. An index that is a standardized measure used in observing infants over time is approximately normal with a
mean of XXXXXXXXXXand a standard deviation of XXXXXXXXXXWhat index score is greater than 33% of the population index
scores?
a. -0.44
. 52.24
c XXXXXXXXXX
d XXXXXXXXXX
e. 91.60

12. In 2019, 15.9% of Broadway actors were acting in their first role on Broadway. Suppose we took a survey of
38 Broadway actors and found that 18.4% of the actors we surveyed were first-timers. What are the mean and
standard deviation for the sampling distribution of p^?
a. Mean: XXXXXXXXXX, Standard Deviation: XXXXXXXXXX
. Mean: XXXXXXXXXX, Standard Deviation: XXXXXXXXXX
c. Mean: XXXXXXXXXX, Standard Deviation: XXXXXXXXXX
d. Mean: XXXXXXXXXX, Standard Deviation: XXXXXXXXXX
e. Mean: XXXXXXXXXX, Standard Deviation: XXXXXXXXXX

14. In which of the following scenarios can we assume that the sampling distribution is approximately normal?

I. The population distribution for a mean is approximately normal, but the sample size is 5.

II. The population distribution for a mean is not normal, but the sample size is 25.

III. The population distribution for a mean is not normal, but the sample size is 50.

IV. The sample size for a proportion is large enough that np and n(1-p) are both 15.

V. The sample size for a proportion is large enough that np and n(1-p) are both 20.
a. I, II, III, V
. III, IV, V
c. I, III, V
d. I, III, IV, V
e. I, II, III, IV, V
15. In XXXXXXXXXXthe CDC reported that 14.0% of US adults are smokers. Suppose you take a random sample of 30
smokers and find that the proportion of them who are cu
ent smokers is 16.7%.What is the mean and the
standard deviation of the sampling distribution of p^ ?
a. mean = XXXXXXXXXX, standard deviation = XXXXXXXXXX
. mean = XXXXXXXXXX, standard deviation = XXXXXXXXXX
c. mean = XXXXXXXXXX, standard deviation = XXXXXXXXXX
d. mean = XXXXXXXXXX, standard deviation = XXXXXXXXXX

16. The National Center for Health Statistics reports that the mean systolic blood pressure for males XXXXXXXXXXto 44
years of age is XXXXXXXXXXA medical director wants to test whether the mean systolic blood pressure of company
executives between the ages of XXXXXXXXXXand XXXXXXXXXXis different from that of the general population. He asks the
company's statistician to give him the results of this hypothesis test, but instead he receives the 95%
confidence interval of

## Answer To : 1. The United States Forest Service is interested in determining the percentage of acreage in...

Retuparna answered on Sep 10 2021
PFA
Question 1
(e) 2.3%
Question 7
(b) The probability cannot be calculated because the distribu
tion is not normal; it is skewed left.
Question 8
(e) 91.60
Question 12
(c) Mean : 0.159, Standard deviation : 0.059
Question 14
(e) I,II,III,IV,V
Question 15
(c) Mean : 0.140, Standard...
SOLUTION.PDF