### Standard Deviation, Independent Variable – Final Test – STATS

The key terms in these Statistics chapters include Distribution, Variable, Quasi-independent variable, Standard Deviation, Normal Distribution, Correlation, z-score Distribution, Sample, Population, – Final Test – Stats

A doctor is measuring children’s heights to the nearest inch and obtains scores such as 40, 41, 42, and so on. What are the real limits for a score of X = 42?

41.5 and 42.5

A quasi-independent variable is most similar to and consistent with which of the following terms?

Non-equivalent groups research study

Which of the following statements is consistent with a research study conducted with the correlational method?

Two variables are measured, and there is only one group of participants.

Assuming that SS Y is constant in a research study, which of the following correlations would have the largest SS residual?

r = – 0.10

A normal distribution has a mean of µ = 60 with σ = 8. For this population, which is the X value that corresponds to the third quartile?

##### X = 65.36

Which proportion of a normal distribution is located between the mean and z = +1.40?

0.4192

In order to determine if 10 points below the mean on an exam is an extreme negative score, the _____ needs to be known.

Standard deviation

2% of scores fall between the z scores ________ and ________.

2;3

In a STANDARD NORMAL DISTRIBUTION, approximately ________% of scores fall within 2 standard deviations from the mean

96

A z-score distribution ________ has a mean of ________.

Always; 0

What are the values for SS and variance for the following sample of n = 4 scores? Scores: 1, 3, 0, 4

SS = 10 and variance = 3.33

Which set of scores below has the smallest standard deviation? a. 5, 11, 42, 22 b. 27, 105, 10, 80 c. 145, 143, 145, 147 d. 11, 17, 31, 53

b. 145, 143, 145, 147

A doctor is measuring children’s heights to the nearest inch and obtains scores such as 40, 41, 42, and so on. What are the real limits for a score of X = 42?

41.5 and 42.5

A quasi-independent variable is most similar to and consistent with which of the following terms?

##### Non-equivalent groups research study

Which of the following statements is consistent with a research study conducted with the correlational method?

Two variables are measured, and there is only one group of participants.

Assuming that SS Y is constant in a research study, which of the following correlations would have the largest SS residual?

r = – 0.10

The sum of the squared deviation scores is SS = 20 for a sample of n = 6 scores. What is the variance for this sample?

s2 = 4

The law of large numbers states that larger samples are _____.

Usually more representative of a population

If the individuals in a sample have characteristics that are noticeably different from the individuals in the population, then the sample is said to be ____.

Biased

The most commonly used sampling method in psychological research is probably ____ sampling

Convenience

A systematic sample does not qualify as a true random sample because ____.

The selections are not independent of each other

There’s a type of validity that usually needs multiple research studies over a long period of time. Which is it?

##### Construct

Consider the mathematical expressions of (Σ X) 2 and Σ X 2. A valid generalization is that _____.

The first equation will yield a higher computed value

Standard Deviation Final Test – Statistics

Which of the following is a description of DATA (rather than a datum)?

Individual scores of 15 participants on a problem-solving task

For a research study examining how participant gender influences support for equality in society, participant gender is an example of which kind of variable?

Quasi-independent variable

A vertical line is drawn through a normal distribution at z = -1.20. Which proportion of the distribution is on the right-hand side of the line?

0.8849 (body)

A class consists of 10 male and 30 female students. A random sample of n = 3 students is selected with replacement. If the first two students are both females, what is the probability that the third student is a male?

p = 10/40

Which of the following is a requirement for a random sample?

a. There must be sampling with replacement.
b. Every individual has an equal chance of being selected.
c. The probabilities cannot change during a series of selections.
d. All of the above are correct

Which position in a distribution corresponds to a z-score of z = -1.00?

##### Below the mean by 1 standard deviation

Tom scores an X = 43 on an exam with a mean of µ = 52. Tom’s score is associated with a z-score of -1.80. What is the value for the exam standard deviation?

σ = 5

Under which circumstance is a score that is 15 points above the mean an extreme score relatively far from the mean?

When the population standard deviation is much smaller than 15

A sample has M = 71 and s = 3. In this sample, what is the X value corresponding to z = +1.33?

##### X = 75

If an entire population with µ = 60 and σ = 8 is transformed into z-scores, then the distribution of z-scores will have a mean of _____ and a standard deviation of _____.

µ = 0; σ = 1.

A population of scores has µ = 10 and σ = 2. If every score in the population is multiplied by 4, then what are the new values for the mean and standard deviation?

µ = 40 and σ = 8

Consider a population that has a score of X = 15 associated with a z-score of +1.50. What does this z-score indicate about the location of X = 15?

A score of X = 15 is 1.5 standard deviations above the mean.

Corey scores X = 70 on his first exam, for which the entire class scored a mean of µ = 78 and standard deviation of σ = 6. The instructor wants to standardize the distribution of exam scores to have µ = 100 and σ = 15. What will Corey’s grade on the exam be in the new distribution?

X = 80

A score that is 3 points lower than the sample mean has a z-score of z = -0.25, and a score of X = 44 has a z-score of -0.75. What is the sample mean?

##### M = 53

A doctor is measuring children’s heights to the nearest inch and obtains scores such as 40, 41, 42, and so on. What are the real limits for a score of X = 42?

41.5 and 42.5

A quasi-independent variable is most similar to and consistent with which of the following terms?

##### Non-equivalent groups research study

Which of the following statements is consistent with a research study conducted with the correlational method?

Two variables are measured, and there is only one group of participants.

Assuming that SS Y is constant in a research study, which of the following correlations would have the largest SS residual?

r = – 0.10

Which of the following is a requirement for a random sample?

a. There must be sampling with replacement.
b. Every individual has an equal chance of being selected.
c. The probabilities cannot change during a series of selections.
d. All of the above are correct

Which position in a distribution corresponds to a z-score of z = -1.00?

Below the mean by 1 standard deviation

Tom scores an X = 43 on an exam with a mean of µ = 52. Tom’s score is associated with a z-score of -1.80. What is the value for the exam standard deviation?

σ = 5

Under which circumstance is a score that is 15 points above the mean an extreme score relatively far from the mean?

When the population standard deviation is much smaller than 15

Standard Deviation Final Test – Statistics

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