Quiz 4

Question 1

Random samples of size 525 are taken from a process (an infinite population) whose population proportion is 0.3. The standard deviation of the sample proportions (i.e, the standard error of the proportion) is

a. 0.0200
b. 0.3000
c. 0.0004
d. 0.2100

Answer 1

0.0200

Question 2

Cluster Sampling is:

a. None of the alternative answers is correct
b. a probability sampling method
c. a nonprobability sampling method
d. the same as convenience sampling

Answer 2

A probability sampling method

Question 3

A simple random sample of size n from a finite population of size N is to be selected. Each possible sample should have

a. a probability of N/n of being slected
b. a probability of 1/n of being selected
c. the same probability of being selected
d. a probability of 1/N of of being selected

Answer 3

The same probability of being selected

Question 4

A theorum that allows us to use the normal probability distribution to approximate the sampling distribution of sample means and sample proportions whenever the sample size is large is known as the

a. approximation theorum
b. normal porobability theorum
c. central normality theorum
d. central limit theorum

Answer 4

CENTRAL LIMIT THEORUM

Question 5

The probability distribtuion of all possible values of teh sample proportion p-bar is the

a. sampling distrubution of x bar
b. probability density function of p-bar
c. sampling distibution of p-bar
d. same as p-bar, since it considers all possible values of te sample proportion

Answer 5

Sampling distribution of p-bar

Question 6

A numerical measure from a population, such as a population mean, is called

a. the mean division
b. a parameter
c. a statistic
d. a sample

Answer 6

A parameter

Question 7

A population has a mean of 84 and a standard deviation of 12. A sample of 36 observations will be taken. The probability that the sample mean will be between 80.54 and 88.9 is

a. 0.7200
b. 0.0347
c. 0.9511
d. None of the alternative answers are correct

Answer 7

0.9511

Question 8

Which of the following is(are) point estimator(s)?

a. u
b. o
c. All of the asnwers are correct
d. s

Answer 8

s

Question 9

Four hundred registered voters were randomly selected asked whether gun laws should be changed. Three hundred said “yes” and one hundred said “no”.

The point estimate of the proportion in the population who will respond “no” is

a. 0.75
b. 75
c. 0.50
d. 0.25

Answer 9

0.25

Question 10

As the sample size increases, the

a. standard error of the mean increases
b. standard error of the mean decrease
c. population mean increases
d. standard deviation of the population decreases

Answer 10

standard error of the mean decreases

Question 11

In point estimation, data form the

a. a population is used to estimate the population parameter
b. sample is used to estimate the population parameter
c. sample is used to estimate the sample statistic
d. None of the alternative ANSWERS is correct

Answer 11

sample is used to estimate the population parameter

Question 12

A sample of 25 observations is taken from a process (an infinite population). The sampling distribution of (blank??) is

a. approximately normal is np > 30 and N(1-p) > 30
b. not normal since n <30
c. approximately normal because (blank) is always normally distributed
d. appriximately normal if np(greater or equal to)5 and n(1-p) (greater or equal to) 5

Answer 12

Approximately normal if np > 5 and n(1-p)>5

Question 13

The standard deviation of (blank??) is referred to as the

a. standard error of the mean
b. standard x
c. sample mean deviation
d. sample standard mean

Answer 13

standard error of the mean

Question 14

A random sample of 121 bottles of cologne showed an average content of 4 ounces. It is known that the standard deivation of the contents (i.e., of the population) is 0.22 ounces.

In this problem the 0.22 is

a. the average content of colognes in the long run
b. a statistic
c. a parameter
d. the standarrd error of the mean

Answer 14

A parameter

Question 15

A population has a mean of 180 and a standard deivation of 24. A sample of 64 observations will be taken. The probability that the mean from that sample will be between 183 and 186 is:

a. 0.8185
b. 0.4772
c. 0.3413
d. 0.1359

Answer 15

0.1359

Question 16

A numerical measure from a sample, such as a sample mean, is known as

a. A statistic
b. a pararmeter
c. the central limit theorum
d. the mean deviation

Answer 16

A statistic

Question 17

A single numerical value used as an estimate of a population parameter is known as

a. a point estimate
b. a population parameter
c. a parameter
d. both a parameter or a population parameter are correct

Answer 17

A point estimate

Question 18

Whenever the population has a normal probability distribution, the sampling distribution of (blank??) is a normal probability distribution for

a. any sample size
b. only small sample sizes
c. only large sample sizes
d. only samples of size thirty or greater

Answer 18

Any sample size

Question 19

A random sample of 150 people was taken from a very large population. Ninety of the people in the sample were females. The standard error of the proportion of females is

a. 0.0016
b. 0.2400
c. 0.1600
d. 0.0400

Answer 19

0.0400

Question 20

As a general rule, the sampleing distribution of the sample proportions can be approximated by a normal probability distribtuion whenever

a. n(1-p) >(greater or equal to) 5
b. np >(greater or equal to ) 5
c. Both np >(greater or equal to) 5 and n(1-p)>(greater or equal to) 5 are true
d. n >(greater or equal to) 30

Answer 20

BOTH np>5 and n(1-p)>5 are true

Question 21

Stratified random sampling is a method of selecting a sample in which

a. the sample is first divided into groups, and then random samples are taken from each group
b. various strata are selected from the sample
c. the population is first divided into groups, and then random samples are drawn from each group
d. None of the alternative answers is correct

Answer 21

The population is first divded into groups, and then random samples are drawn from each group

Question 22

The following data was collected from a simple random sample from a process (an infinate population)

13 15 14 16 12

The point estimate of the population standard deviation is

a. 2.000
b. 1.581
c. 2.500
d. 1.414

Answer 22

1.581

Question 23

The fact that sampling distribution of the sample mean can be approximated by a normal probability whenever the sample size is large is based on the

a. central limit theorem
b. All of these answers are correct
c. assumption that the population has a normal distribution
d. fact that there are tables of areas for the normal distribution

Answer 23

Central Limit Theorem

Question 24

A simple random sample from a process (an indinite population) is a sample selected such that

a. each element selected comes from the same population
b. each element selected comes from the same population and each element is selected independently
c. each element is selceted independently
d. the porbabilty of being selected changes

Answer 24

Each element selected comes from the same population and each element is selected independently

Question 25

The probability distribtuion of all possible values of the sample mean is called the a. standard error b. random variation c. central probability distribtion d. sampling distribution of the sample mean

Answer 25

Sampling distribution of the sample mean