Question

1. At a large block party, there are 50 men and 40 women. You want to ask opinions about how to improve the next party. You choose at random five of the men and separately choose at random four of the women to interview.

(a) What is the probability that any of the 50 men is in your random sample of five men to be interviewed? What is the probability that any of the 40 women is in your random sample of four women to be interviewed?

(b) If you have done the calculations correctly in part (a), the probability of any person at the party being interviewed is the same. Why is your sample of nine men and women not an SRS of people from the party?

Answer #1

a) Probability of drawing a particular man in the 5 men selected out of the 50 men is computed here as:

Similarly now the probability of drawing a particular woman in the 4 women selected out of the 40 women is computed here as:

**Therefore 0.1 is the required probability here
too.**

b) The drawing of a random sample in this case is not a case of
a simple random sampling but a case of a **stratified random
sampling** . This is because we are not drawing the 9 people
randomly from 90 people but we are making sure that we are drawing
5 men from a subgroup of 50 men and then 4 women from the subgroup
of 40 women.

Sampling. What kind of sample? At a party, there are 30 students
over age 21 and 20 students under age 21. You choose at random six
of those over 21 and separately choose at random four of those
under 21 to interview about attitudes toward alcohol. A) Have you
given every student at the party the same chance to be interviewed:
what is that chance? B) Is this a simple random sample or another
kind of sample that you are...

You have asked a sample of men and women in your community
whether or not they intend to vote for a gas tax to raise money for
public transportation. Of the men, 15 said "yes" and 20 said "no";
of the women, 25 said "yes" and 10 said "no". Assuming that proper
experimental procedures have been followed, what can you
conclude?
(note: if you determine that the df = 1, or an expected
frequency is less than 5, then you...

What type of shopping websites do males aged 18 to 34 visit?
About 50% of male Internet users in this age group visit an auction
site (such as eBay) at least once a month.
(a) If we interview a random sample of 14 male Internet users
aged 18 to 34, what is the probability that exactly 11 of the 14
have visited an auction site in the past month? (Round your answer
to four decimal places.)
b) Suppose that we...

What type of shopping websites do males aged 18 to 34 visit?
About 50% of male Internet users in this age group visit an auction
site (such as eBay) at least once a month.
(a) If we interview a random sample of 13 male Internet users
aged 18 to 34, what is the probability that
exactly 8 of the 13 have visited an auction site
in the past month? (Round your answer to four decimal
places.)
(b) Suppose that we...

1. Suppose you want to determine whether women and men
experience anxiety differently in response to the
dissolution of romantic relationships. You administer Zung’s
self-rating anxiety scale to a random sample of 20 men and 20 women
who just went through a break-up.
M
s
n
Women:
35.5
14.66
20
Men:
49.3 18.50
20
(s represents standard deviation. In order to calculate t value,
you need to transfer it back to SS.)...

20 women and 30 men between 18 to 60 years old and the
number of hours that they work. These information would be your
populations. For each group find the followings:
20 Women Ages = 19, 23, 40, 18, 60, 50, 21, 30, 33, 28,
33, 35, 28, 24, 28, 18, 19, 22, 25, 50
20 women work hours weekly = 40, 24, 30, 31, 19, 10, 21,
5, 40, 9, 8, 40, 37, 12, 20, 40, 20, 10, 40,...

(1 point) To estimate the mean height μ of male students on your
campus, you will measure an SRS of students. Heights of people of
the same sex and similar ages are close to Normal. You know from
government data that the standard deviation of the heights of young
men is about 2.8 inches. Suppose that (unknown to you) the mean
height of all male students is 70 inches.
(a) If you choose one student at random, what is the...

1/ A physical therapist wants to determine the difference in the
proportion of men and women who participate in regular sustained
physical activity. What sample size should be obtained if she
wishes the estimate to be within five percentage points with 95%
confidence, assuming that
(a)she uses the estimates of 21.8% male and
18.3% female from a previous year? n = (Round up to the nearest
whole number.)
(b) she does not use any prior estimates?
2/ A survey asked,...

Probability and Statistics
Could you please solve the following questions with specifying the
answers
A. When would you use a t-test rather than a
z-test?
a. when you need to use the standard deviation of a small
sample
b. when the mean is very large
c. when you want the confidence interval to be narrower
B. Twenty-five weighings of a small object on a
sensitive scale result in average of 8.23 grams. If the standard
deviation σ of weighings on...

You are asked to do a study of shelters for abused and battered
women to determine the
necessary capacity I your city to provide housing for most of
these women. After recording data
for a whole year, you find that the
mean number
of women in shelters each night is
250
, with a
standard deviation of 75
. Fortunately, the distribution of the number of women in the
shelters
each night is normal, so you can answer the following...

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 9 minutes ago

asked 10 minutes ago

asked 23 minutes ago

asked 23 minutes ago

asked 27 minutes ago

asked 30 minutes ago

asked 30 minutes ago

asked 33 minutes ago

asked 39 minutes ago

asked 41 minutes ago

asked 45 minutes ago

asked 45 minutes ago