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Flag this Question Question 11 What does the second column in a frequency table show? Group of answer choices

a)categories (or levels) of the variable

b)probability of the variable

c)frequencies

d)percentages

Flag this Question Question 122 pts A college instructor wants to know the amount of time her students spend on studying every day so she collected the information from everyone in her class. The data yielded a mean of 90 minutes and a standard deviation of 8 minutes. What is the variance?

Group of answer choices

64

8

2.

83

Question 132 pts

What is the standard deviation of the sample that consists of 3, 5, 9, 11, 15?

Group of answer choices

4.27

1.72

18.24

91.2

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Question 142 pts

You randomly select someone from a group of 20. Eight people in the group are females. What is the probability that the person you draw is a male?

Group of answer choices

.73

.60

.40

.12

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Question 152 pts

What minimum Z score does a student need to get to be ranked in the top 5% of her/his class? (Use the Z table)

Group of answer choices

around 2.33

around 1.28

around 1.65

around 0.05

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Question 162 pts

Explain why we make an inference about a population using a sample.

Group of answer choices

It is typically not possible or practcal to study the entire population of interest.

Samples are easier to analyze using mathematical analysis.

A sample is often vastly different of the population from which it is drawn.

We can's study a population of interest directly because it really does not exist.

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Question 172 pts

Meditation is proposed by some to improve the overall quality of sleep. A researcher wants to examine the effect of meditation on the number of minutes spent in deep sleep. She is not sure, however, if meditation will increase or decrease the number of minutes in deep sleep. Should she conduct a one-tailed or two-tailed hypothesis test, and why?

Group of answer choices

One-tailed because only one variable, sleep, is examined

One-tailed because meditation is proposed to improve sleep quality.

Two-tailed because there are two variables—whether or not people meditate and whether deep sleep is increased.

Two-tailed because the researcher is interested in any effect of meditation on deep sleep, increase or decrease.

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Question 182 pts

In a housing project there are 180 households in which English is usually spoken, 80 in which Spanish is usually spoken, and 40 in which the language is other than English or Spanish. A researcher approaches a house at random to conduct an interview. What is the chance that the usual language in that household will NOT be English?

Group of answer choices

.60

.33

.40

.12

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Question 192 pts

Interpret this statement: "We fail to reject the null hypothesis at alpha level of .05."

Group of answer choices

The probability was less than .05 that a sample like this could have been obained when the null hypothesis was true.

The probability was more than .05 that a sample like this could have been obtained when the null hypothesis was true.

The probability was less than .05 that a sample like this could have been obained when the null hypothesis was false.

The probability was more than .05 that a sample like this could have been obained when the null hypothesis was false.

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Question 202 pts

In a single throw of a die, what is the probability of attaining a number that is 2 or lower?

Group of answer choices

.67

.50

.20

.33

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Question 212 pts

What is a valid reason for choosing a two-tailed test even when a given direction can be predicted?

Group of answer choices

Statistical programs are set to default to two-tailed tests.

One-tailed tests are more effective in preventing Type I errors.

Two-tailed tests allow for the possibility that the finding could be in either direction.

A two-tailed test is more likely to produce a significant result.

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Question 222 pts

Why is a one-tailed test considered a more lenient test than a two-tailed test on a sample of data?

Group of answer choices

The alpha is multiplied by two in order to figure the size of the significance area in each tail for a two-tailed test, resulting in more alpha in a two-tailed test.

The tail areas in a two-tailed test are combined in one tail in a one-tailed test, making the critical value less extreme in a one-tailed test than in a two-tailed test.

The one-tailed test has only one critical value, and the two-tailed test has two critical values that both need to be exceeded.

A one-tailed test only tests one hypothesis, but a two two-tailed test tests two hypotheses.

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Question 232 pts

How does a two-tailed test compared to a one-tailed test when given a sample statistic and a fixed alpha level?

Group of answer choices

The critical value to be compared to the statistic would be less extreme with a two-tailed test.

The critical value to be compared to the statistic would be more extreme with a two-tailed test.

The total significance area in the comparison distribution is larger in a two-tailed test.

The total significance area in the comparison distribution is smaller in a one-tailed test.

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Question 242 pts

The time spent on an exam by a class of 100 students is normally distributed with a mean of 50 minutes and a standard deviation of 8 minutes. Using the percentage approximations for the normal curve, what is the percentage of the population of all exam takers that would spend between 50 to 62 minutes on the exam? (Use of Z table is necessary)

Group of answer choices

41.92%

43.32%

8.08%

6.68%

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Question 252 pts

What is the probability of drawing a score from a normal distribution of scores that can be converted into a Z score between +1 and -2? (Use the Z table)

Group of answer choices

.9544

.6826

.3414

.8185

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Question 262 pts

A graduating class in a local high school were surveyed, and 60% of the students have decided to attend Arizona State University. If I randomly draw a student from the graduating class, what is the probability that the chosen student will be attending ASU?

Group of answer choices

.40

40%

.60

60%

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Question 272 pts

What happens as the overlap between the distribution of population 2 and the inferred distribution of population 1 increases?

Group of answer choices

The effect size is smaller.

The effect size is larger.

The significance level rises.

The significance level falls.

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Question 282 pts

Why would a researcher complete a power analysis before conducting a study?

Group of answer choices

To determine the number of participants required for the study.

To determine whether the study should be conducted or not.

To determine the alpha level for the study.

To determine whether to conduct a one-tailed or a two-tailed test with the data.

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Question 292 pts

The raw effect size of a study be converted to a standardized effect size by _______________________.

Group of answer choices

dividing the difference between the two population means by the population standard deviation.

dividing the difference between the two population means by the square root of N

dividing the difference between the two population means by the standard error of the sampling distribution

dividing the difference between the two population means by the sample size

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Question 302 pts

It is hypothesized that bird owners have fewer doctor's visits compared to the general population. To conduct a one-tailed hypothesis test, the researcher sets the α (significance) level at .05. What should be the critical Z value based on the Z table?

Group of answer choices

1.96

-1.645

+1.96 and -1.96

-1.65 and +1.65

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Question 312 pts

A new type of orange has been developed to be bigger than the typical orange, which average 8 oz in weight. The critical Z value for a hypothesis test is 1.28 and the standard error is 2 oz. What is the minimum weight (in oz) of the sample of new oranges to yield a significant test result?

Group of answer choices

10.56+

13.88+

9+

5.04+

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Question 322 pts

A study was conducted on the effects of praise on children's school grades. If the study has high statistical power, it means that the probability is high for ____________.

Group of answer choices

getting a significant test result when praise actually has the predicted effect on grades

not getting a significant result when praise does not actually have the predicted effect on grades

getting a significant test result even when praise does not necessarily have the predicted effect on grades

not getting a significant test result even when praise actually has the predicted effect on grades

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Question 332 pts

A market researcher wants to know if Toyota vehicles have significantly higher MPGs compared to the national statistics. She sets the α (significance) level at .10 for a one-tailed test. The Z statistic calculated from the Toyota sample is 1.62. What is the conclusion from this hypothesis test?

Group of answer choices

The null hypothesis is rejected and Toyota vehicles have significantly higher MPGs compared to the national data.

The null hypothesis is rejected and Toyota vehicles do not have significantly higher MPGs compared to the national data.

The null hypothesis is not rejected and Toyota vehicles have significantly higher MPGs compared to the national data.

The null hypothesis is not rejected and Toyota vehicles do not have significantly higher MPGs compared to the national data.

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Question 342 pts

What is a a sampling distribution?

Group of answer choices

It is a distribution of the means of all possible samples (of a particular size) drawn from a population.

It has a mean and standard deviation which are are smaller than those of the original population from which it is derived.

It has a larger variability compared to the original population from which it is derived.

It is composed of Z scores converted from the original scores in the population.

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Question 352 pts

Compared to a sampling distribution with a mean of 100 and a standard error of 20, what is the Z statistic for the sample that consists of 98, 102, 108, 112.

Group of answer choices

.25

2.5

-.25

-2.5

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Question 362 pts

A teacher conducted a study to see if the students in his school performed significantly worse than the national average on a standardized math test. He calculated the Z statistic to be -1.78 while the critical value for the hypothesis test was -1.645. He would conclude that ___.

Group of answer choices

the null hypothesis was rejected and the students in his school performed significantly worse than the national average.

the null hypothesis was rejected and the students in his school did not perform significantly worse than the national average.

the null hypothesis could not be rejected and the students in his school pefromed significantly worse than the national average.

the null hypothesis could not be rejected and the students in his school did not perform significantly worse than the national average.

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Question 372 pts

The average weight of 49 young males is 170 lbs. This sample is compared to the general population of males in the same age range. The general population mean is 173 lbs and the standard deviation is 5 lbs. What is the standardized effect size of this test?

Group of answer choices

-0.60

.5

.3

3

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Question 382 pts

In a study on work hours, a sample of ASU psychology online students are compared to the general population of ASU online students and the Z statistic for the sample is -1.68. With a one-tailed test with an alpha level of .05, what is the conclusion of the hypothesis test?

Group of answer choices

Fail to reject the null hypothesis.

Reject the null hypothesis.

Reject the alternative hypothesis.

Reject both the null and the alternative hypotheses.

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Question 392 pts

What is the purpose of finding the standardized effect size of a study?

Group of answer choices

To evaluate the practical importance of a result

To double check the test statistic for accuracy

To evaluate the null hypothsis

To see if the hypothesis test is significant or not

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Question 402 pts

What is the term for the standard deviation of the distribution of means (the sampling distribution)?

Group of answer choices

standard error

standard deviation

standard variance

shared variance

Answer 1