exam

For a population with µ = 84 and σ = 4, what is the z-score corresponding to X = 80?

-1.00

A population has SS = 100 and σ2 = 4. What is the value of Σ(X - µ) for the population? Hint: start with the SS population formula and take the square root of both sides.

10

A sample of n = 5 scores has a standard deviation of s = 5. What is the value of SS, the sum of the squared deviations for this sample?

100

A population has SS = 100 and σ2 = 5. How many scores are in the population?

20 Variance is the same as σ2 Variance population formula is = σ2 = therefore: Thus Important to note that this is a population, not a sample with N -1.

A population of N = 10 scores has a standard deviation of σ = 2. What is the value of SS, the sum of the squared deviations, for this population?

40 Variance is the same as σ2 so 22 = 4. Hence the variance is 4. Variance 4 = 4 X 10 = 40

The sum of the squared deviation scores is SS = 50 for a population of N = 10 scores. What is the variance for this population?

5 Variance formula for a population is SS 50 = 5 N 10

For the following grouped frequency distribution table of exam scores, how many students had scores higher than X = 54? X f 60-64 3 55-59 4 50-54 5 45-49 2 40-44 1

7

A distribution of scores is positively skewed. Which is the most probable order, from smallest to largest, for the three measures of central tendency?

Mode, median, mean

Which statement accurately describes the proportions in the tails of a normal distribution?

Proportions in both the left-hand and right-hand tails tend to be relatively small.

A characteristic, usually a numerical value, which describes a sample is called a _____

statistic

Which of the following statements is consistent with hypothesis testing?

The edges of the distribution of sample means are consistent with the alternative hypothesis.

What is the summation of X - µ? SS = S(X - µ)2 SS = 100 100 = Ʃ(X - µ)2

The square root of Ʃ(X - µ)2 = Ʃ(X - µ). Since you had the square root for one side, you must square root the other side. So, when you take the square root of 100, you get 10. 10 is your answer.

Which type(s) of frequency distribution graph(s) should be used for data that come from a nominal scale of measurement?

bar graphs

What is the shape of a frequency distribution where scores tend to pile up on the right side, tail tapering off to the left.

negatively skewed

A researcher uses an anonymous survey to investigate the television-viewing habits of 100 American adolescents. The researcher plans to make an inference about the television-viewing habits of all American adolescents based on the results of the survey. The entire group of American adolescents is an example of a _____.

population

Which symbol below identifies the sample variance?

s2

Which of the following accurately describes the critical region?

sample means that are very unlikely to be obtained if the null hypothesis is true

Consider a researcher who is exploring new potential treatments for specific forms of cancer. This researcher is extremely focused on avoiding mistakes in concluding that treatments that may very well be effective are ineffective when conducting their research. What should this researcher do?

set a higher alpha level

Which of the following phrases is not consistent with central tendency as a statistical measure

spread of scores

The distribution of z-scores corresponding with a population of scores always has a variance of _____.

σ2 = 1.