Blatchley Chapter 06 Quiz

.

Erica's z-score on a test is 1.1; her actual score is 20 and the mean of the test is 15. What is the standard deviation of the test?

-1.21

1.21

4.55

-4.55

.

Given that Josh's deviation score on a test is -1.25 and the standard deviation of the test is 0.8, what is his z-score?

-1

1

-1.56

1.56

. Under the 3-sigma rule, what is the percentage of observations that will be two or more standard deviations above the mean?

1%

2%

3%

4%

. Which of the following is a benefit of converting raw scores to standard scores?

Allows you to be more likely to find a significant result

Allows you to compare scores from different scales

Allows you to check if your data have been entered correctly

None of the above

. Susan is comparing two data distributions. Distribution A has a standard deviation of 0.23 while Distribution B has a standard distribution of 2.1. Which of the following must be true?

Distribution A has a larger spread than Distribution B.

Distribution B has a larger spread than Distribution A.

Distribution A and Distribution B are both positively skewed.

There is insufficient information to make conclusions about the spread of both distributions.

. What is the difference in probability of obtaining a z-score of at least -1.67 and getting a z-score of 1.67 or more?

0

0.0475

0.18

0.0001

. If you obtain an observed z-score that is smaller than a negative critical z in a one-tailed test with an alpha level of 0.05, what should you do?

Fail to reject the null hypothesis

Reject the null hypothesis

Find out the population mean

Calculate the probability of obtaining the observed z-score

. Which of the following is true about z-scores?

Observed z-scores can only be positive if you have a one-tailed hypothesis.

In a two-tailed hypothesis with alpha at .05, you can find critical z by looking up the z-score that corresponds to 0.05.

There is a higher probability in obtaining a z-score of at least -0.1 compared to the probability of obtaining a z-score of at least 1.1.

The z-score that corresponds to the highest probability in a normal distribution is a score of zero.

. Which of the following is a benefit of using standard scores?

Standard scores enable us to more easily compare performance on the test across everyone who takes the test.

Standard scores do not need to fulfill the 3-sigma rule.

Standardized scores retain the original units of measurement which gives us more information on how to interpret the scores.

Standardized scores are less likely to result in Type I error during analysis.

. Ben scored 100 on an intelligence test with a mean of 80 and standard deviation of 10. Fred scored 200 on a different intelligence test with a mean of 150 and standard deviation of 50. Which of the following statements is true?

Ben performed relatively better on his test than Fred did on his.

Ben performed relatively worse on his test than Fred did on his.

Ben and Fred performed equally well on their tests.

There is insufficient information to make a conclusion.

. Jessica would like to standardize scores on a test that she just collected data for. She has the mean of the test. Which of the following is true?

She has enough information to standardize the scores.

She needs to find out the shape of the distribution and the standard deviation to standardize the scores.

She needs to find out the range, mode and median of her data, in addition to the mean, to standardize scores.

None of the above

.

Brianna's z-score is 0.2 on a test with a mean of 60 and standard deviation of 2. What is her raw score?

60.1

60.4

62

64

.

Greg's z-score on a test is -2.1. Which of the following options must be true?

Greg scored better than 90% of other test takers.

Greg scored better than 30% of other test takers.

Greg scored worse than 99% of other test takers.

Greg scored worse than 98% of other test takers.

. How many observed values are included in the formula for a z-score?

0

1

2

3

. Which of the following options must be true for a z-test with a one-tailed hypothesis and an alpha level of .01?

The rejection area is the area under the graph to the left of a z-score of zero.

The rejection area is bigger than the area outside of it.

The rejection area is a tiny tail on the right of the graph.

The rejection area corresponds to a probability of .01.

. Ben would like to use a z-test to find out his relative ranking on a computer game. He has the average score of everyone in the game and his own personal score. However, he is unable to find the standard deviation of all scores. Which of the following is true?

Ben should proceed with the z-test by guessing the standard deviation because the z-test is robust and will give him a good estimate of his position relative to others.

Ben is unable to find his relative ranking without the standard deviation.

If Ben's score is very much larger than the average score, then he can conclude that he is one of the game's best players.

None of the above.

.

Joseph had a score of 30 on a test with a mean of 35 and standard deviation of 5. What is Joseph's percentile rank on the test?

5%

15.9%

31.8%

84.1%

. Which of the following is not true about z-scores in a distribution?

Extreme scores have a lower probability of occurring as compared to less extreme scores.

Obtaining an observed z-score that matches the population mean will result in a z-score of zero.

The probability of obtaining a z-score that is less than the mean is negative.

Z-scores allow for comparison of relative performance across different types of measures.

. The area under the graph of a standard normal distribution corresponds to:

The sum of all the z-scores

Probability

The product of the standard deviation and the mean

None of the above

. In a perfectly normal distribution, z-scores that are negative correspond to raw scores that are _________ the mode of the distribution.

Above

Below

Representative of

There is insufficient information to complete the statement.

. The 3-sigma rule is:

An estimation of the relationship between the standard deviation and the probability of where scores fall in a normal distribution.

An estimation of the relationship between the mean, median and mode in a normal distribution.

An estimation of sigma-cubed in a normal distribution that has been standardized.

An estimation of the distance between the observed z-score and the population mean as a function of the spread of the distribution.

.

Natalia's z-score is 1.18 on a test with a mean of 90 and standard deviation of 2. Which of the following options correctly describes the steps to obtain Natalia's raw score?

Divide 1.18 by 2 and add 90.

Multiply 1.18 by 2 and add 90.

Divide 90 by 2 and multiply by 1.18.

Divide 90 by 1.18 and multiply by 2.

. What is the probability of obtaining a z-score of -0.15 or more?

56%

44%

50%

37%

. How much greater is the probability of obtaining a z-score of at least zero compared to the probability of obtaining a z-score of at least 0.7?

12.4%

25.8%

70%

35%

.

If Phillip's score on a test with a mean of 80 and standard deviation of 5 is 68, what is his z-score on the test?

2.4

-2.4

2.0

-2.0

Blatchley Chapter 06 Quiz

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