Transcript Active Learning Questions

Chapter 8
From Samples to Population
Active Learning
Questions
For use with classroom
response systems
Copyright © 2009 Pearson Education, Inc.
Slide 8 - 1
Nine employees of a company are selected at
random and asked how far they commute to work
each day. The distances (in miles) are as follows:
32, 18, 44, 29, 25, 38, 5, 48, 12. Estimate the mean
commute distance of all employees of the
company.
a. It is not possible to estimate the population
mean from this sample data.
b. 26.7 miles
c. 27.9 miles
d. 29 miles
Slide 8 - 2
The ages of employees at a particular company
have a mean of 39. The distribution of sample
means for samples of size 200 is normal with a
mean of 39 and a standard deviation of 0.79.
Suppose you take a sample of size 200
employees from the company and find that their
mean age is 41.3. How many standard deviations
is the sample mean above the mean of the
sampling distribution?
a. 2.3
b. 2.9
c. 41.2
d. 3.2
Slide 8 - 3
Among a random sample of 150 employees of a
particular company, the mean commute distance
is 28.1 miles. This mean lies 0.7 standard
deviations below the mean of the sampling
distribution. If a second sample of 150 employees
is selected, what is the probability that for the
second sample, the mean commute distance will
be at least 28.1 miles?
a. 0.7580
b. 0.5000
c. 0.2420
d. 0.2743
Slide 8 - 4
In one city, there are a total of 1640 5-year-old
children of whom 553 live with one parent only.
Among a sample of 600 of the 5-year-old
children from this city, 223 live with one parent
only. Find the sample proportion of 5-year-old
children who live with only one parent.
a. 0.37
b. 0.34
c. 0.4
d. 223
Slide 8 - 5
There are 13,339 eligible voters in one town.
Among a sample of 828 eligible voters from this
town, 396 say that they plan to vote in the next
mayoral election. Based on this sample, estimate
the number of eligible voters in this town who
will not vote in the next mayoral election.
a. 6959
b. 432
c. 6380
d. 0.52
Slide 8 - 6
12% of the residents of one town are aged over
70. The distribution of sample proportions for
samples of 140 residents is normal with a mean
of 0.12 and a standard deviation of 0.027.
Suppose that you select a sample of 140 residents
and find that the proportion aged over 70 in the
sample is 0.08. What is the probability that a
second sample would be selected with a
proportion greater than 0.08?
a. 0.08
b. 0.12
c. 0.0668
d. 0.9332
Slide 8 - 7
What is the margin of error for a sample size =
1225, sample mean = 214, and standard deviation
= 98?
a. 0.56
b. 5.6
c. 56
d. 560
Slide 8 - 8
At one hospital, a random sample of 100 women
giving birth to their first child is selected. Among
this sample, the mean age was 25.7 with a
standard deviation of 5.1. Estimate the mean age
of all women giving birth to their first child at
this hospital. Give the 95% confidence interval
two decimal places.
a. 24.68 to 26.72
b. 20.6 to 30.8
c. 25.21 to 26.21
d. 15.5 to 35.9
Slide 8 - 9
A medical researcher wishes to estimate the mean
systolic blood pressure of heart surgery patients
the day following surgery. She desires a margin
of error of 1.6 mm Hg. Past studies suggest that a
population standard deviation of 43 mm Hg is
reasonable. Estimate the minimum sample size
needed to estimate the population mean with the
stated accuracy.
a. 53.75
b. 0.0744
c. 2889
d. 137.6
Slide 8 - 10
A government survey conducted to estimate the
mean price of houses in a metropolitan area is
designed to have a margin of error of $8000.
Pilot studies suggest that the population standard
deviation is $56,000. Estimate the minimum
sample size needed to estimate the population
mean with the stated accuracy.
a. 196
b. 225
c. 256
d. 289
Slide 8 - 11
A researcher collects the weight (in pounds) of a
random sample of 32 new born babies, born at a
particular hospital. Give the 95% confidence
interval to two decimal places. The sample mean
is 7.19 pounds and the standard deviation is
0.844 pounds.
a. 7.16 to 7.22
b. 7.04 to 7.33
c. 7.14 to 7.24
d. 6.89 to 7.49
Slide 8 - 12
A researcher wishes to estimate the proportion of
left-handers among a certain population. In a
random sample of 900 people from the
population, 74% are left-handed. Find the margin
of error for the 95% confidence interval.
a. 0.0146
b. 0.0292
c. 0.0493
d. 0.0173
Slide 8 - 13
A researcher wishes to estimate the proportion of
left-handers among a certain population. In a
random sample of 990 people from the
population, 36.4% are left-handed. Find the 95%
confidence interval for the population proportion
of left-handers to four decimal places.
a. 0.3334 to 0.3946
b. 0.3487 to 0.3793
c. 0.6054 to 0.6666
d. 0.6207 to 0.6513
Slide 8 - 14
A population proportion is to be estimated.
Estimate the minimum sample size needed to
achieve a margin of error of E = 0.056 with a
95% degree of confidence.
a. 31.9
b. 319
c. 18
d. 180
Slide 8 - 15
The college daily reported: “600 students living in
university housing were polled. 360 said that they
were satisfied with their living conditions. Based on
this survey we conclude that 60% of students living
in dormitories are satisfied. The margin of error of
the study is 4 percentage points (with a 95% degree
of confidence).” Which statement is correct?
a. There is not enough information to determine whether
the margin of error is consistent with the sample size.
b. The stated margin of error could have been achieved
with a smaller sample size.
c. A larger sample size should be used to achieve the
stated margin of error.
d. The margin of error is consistent with sample size.
Slide 8 - 16