Homework 3

A sample consists of n = 16 scores. How many of the scores are used to calculate the range? 8 4 all 16 2

2

For the following set of scores, the (Σx)^2 is ____. Scores: 10, 10, 8, 3, 6, 5, 2, 7, 3

2916.0000

What is the mean for the following sample of scores? Scores: 1, 2, 5, 4 4 3 12 6

3

For the following frequency distribution table, the mean of x is ____. X Frequency 5 2 4 4 3 1 2 3

3.5

For the following frequency distribution table, what is the value of ΣX? X Frequency 4 3 3 5 2 4 1 2 10 14 24 37

37

For the following set of scores, the Σ(x^2) is ____. Scores: 10, 10, 8, 3, 6, 5, 2, 7, 3

396.0000

The mean is an appropriate measure of central tendency for summarizing data that that have been measured on a nominal scale. True False

False

The mean is a preferred measure for describing skewed distributions. True False

False, it's the median

A population with a mean of μ=6 has Σx=42. How many scores are in the population? N = 252 cannot be determined from the information given N = 7 N = 0.14

N=7

If a negatively skewed distribution has a mean of 50, then the mode is probably greater than 50. True False

True

A sample consists of n = 16 scores. How many of the scores are used to calculate the sample variance? 8 all 16 15 2

all 16

For a perfectly symmetrical distribution with μ = 30, the median would have a value _____. less than 30 cannot be determined from the information given equal to 30 greater than 30

equal to 30

For any set of data, the sum of the deviation scores will always be _____. impossible to determine without more information greater than zero less than zero equal to zero

equal to zero

For the following distribution, state whether you would use the mean or the median to represent the central tendency of the distribution. Scores: 2, 3, 8, 5, 7, 8 Mean Median

mean

For the following distribution, state whether you would use the mean or the median to represent the central tendency of the distribution. Scores: 1.2, 0.8, 1.1, 0.6, 25 median mean

median

A population of scores has μ=50 and σ=10. If every score in the population is multiplied by 2, then the new mean and standard deviation would be ______. μ=50, σ=20 μ=100, σ=20 μ=100, σ=10 μ=50, σ=10

mu=100, sigma=20

The value for the interquartile range is determined by _____. the extremely high scores in the distribution the extreme scores (both high and low) in the distribution the middle scores in the distribution all of the scores in the distribution

the middle scores in the distribution

A population of scores has μ=:50 and \sigma=10σ=10. If 5 points are added to every score in the population, then the new mean and standard deviation would be ______. μ=55, σ=15 μ=50, σ=15 μ=55, σ=10 μ=50, σ=10

μ=55, σ=10

On an exam with a mean of = 70, you have a score of x = 75. Which of the following values for the standard deviation would give you the highest position within the class? 10 5 1 cannot determine from the information given

1

A set of n = 6 scores has a mean of M = 10. Another set of scores has n = 4 and M = 20. If these two sets of scores are combined, what is the mean for the combined group? 14 cannot be determine from the information given 15 16

14

The sum of the squared deviation scores is SS = 60 for a sample of n = 5 scores. What is the variance for this sample? 240 15 12 300

15

For the following sample of scores, the standard deviation is ____. Scores: 7, 2, 4, 6, 4, 7, 3, 7

2.0000

X F 1 1 2 4 3 3 4 1 5 1 For the set of scores in the frequency distribution histogram below, the mode is ____.

2.0000

For the set of scores in the frequency distribution histogram below, the median is ____. X F 1 1 2 4 3 3 4 1 5 1

2.5000

A student kept track of the number of hours she studied each day for a 2-week period. The following daily scores were recorded (scores are in hours): 2.5, 3.2, 3.8, 1.3, 1.4, 0, 0, 2.6, 5.2, 4.8, 0, 4.6, 2.8, 3.3. The mean for this set of scores is ____. (Make sure that you round to two decimal places.)

2.5400

For the set of scores in the frequency distribution histogram below, the mean is ____. X F 1 1 2 4 3 3 4 1 5 1

2.7000

For the following population of scores, the standard deviation is ____. Scores: 1, 9, 8, 5, 7. (Round your answer to two decimal places.)

2.8300

A population has μ = 40 and σ=8. If each score is divided by 2, the new standard deviation will be _____. 4 insufficient information, cannot be determined 8 20

4

For the following sample of scores, the variance is ____. Scores: 7, 2, 4, 6, 4, 7, 3, 7

4.0000

For the following population of scores, the variance is ____. Scores: 1, 9, 8, 5, 7

8.0000

A sample of n = 6 scores has a mean of M = 8. If one score with a value of x = 3 is removed from the sample, what is the mean for the remaining scores? 5 9.6 8 9

9

For a normally distributed set of data, what percentage of these data lie within three standard deviations of the mean? 95% 99.7% 49.85% 68%

99.7%

Given the following values of central tendency for this distribution, determine whether the distribution is symmetrical, positively skewed, or negatively skewed: Mean = 14, median = 16, mode = 18 positively skewed symmetrical negatively skewed

negatively skewed

Given the following values of central tendency for this distribution, determine whether the distribution is symmetrical, positively skewed, or negatively skewed: Mean = 14, median = 12, mode = 10 positively skewed symmetrical negatively skewed

positively skewed

How would you characterize the shape of the frequency distribution histogram shown below? X F 1 1 2 4 3 3 4 1 5 1 negatively skewed positively skewed bimodal symmetrical

positively skewed

What shape would you expect for the distribution of scores from a very hard exam for a large class of students? positively skewed symmetrical negatively skewed normal

positively skewed

Which of the following symbols identifies the sample standard deviation? s^2 σ^2 σ s

s

Given the following values of central tendency for this distribution, determine whether the distribution is symmetrical, positively skewed, or negatively skewed: Mean = 14, median = 14, mode = 14 negatively skewed positively skewed symmetrical

symmetrical

The value of one score in a distribution is changed from x = 20 to x = 30. Which measure(s) of central tendency is (are) certain to be changed? the mode the mean the mean and the median the median

the mean

A population of N = 5 scores produces SS = 20. The variance for this population is ___. σ^2 = 5 σ^2 = 4 s^2 = 5 s^2 = 4

σ^2 = 4