stats final
The sum of the squared deviation scores is SS = 20 for a sample of n = 5 scores. What is the variance for this sample?
5
A sample has a mean of M = 86. If one new person is added to the sample, what effect will it have on the sample mean? a. The sample mean will increase. b. The sample mean will decrease. c. The sample mean will remain the same. d. cannot be determined from the information given
a - mean will increase
what additional info is obtained by measuring on an ordinal scale compared to a nominal scale?
the direction of the differences
What is the purpose for obtaining a measure of central tendency?
used to show an average or representational score of the entire group
T/F - In a population with a mean of μ = 40 and a standard deviation of σ = 8, a score of X = 46 would be an extreme value, far out in the tail of the distribution
F - within the SD
For a sample of n = 16 scores, how many scores are used to calculate the sample variance?
16
A sample of n = 25 scores has M = 20 and s2 = 9. What is the sample standard deviation? (square root of 9)
3
Manipulating an independent variable involves a) exposing participants to at least one level of the independent variable. b) exposing participants to at least 2 levels of the IV c) exposing participants to at least three levels of the IV d) measuring two or more behaviors and determining whether they are related
B - exposing participants to at least 2 levels of the IV
T/F - For a 100-point exam, a score of X = 65 is definitely above the median.
F
T/F A sample has n = 5 scores: 2, 4, 5, 8, and 11. The median for the sample is 6.5
F - 5
T/F - After a researcher adds 5 points to every score in a sample, the standard deviation is found to be s = 10. The original sample had a standard deviation of s = 5.
F - SD stays the same if the constant was added to every score
T/F - A positive deviation always indicates a score that is less than the mean
F - positive deviations are located above the mean
A population of scores has µ = 50 and σ = 5. If every score in the population is multiplied by 3, then what are the new values for the mean and standard deviation?
M = 150, SD = 15
T/F - If a sample has an odd number of scores, at least one individual will have a score exactly equal to the median.
T
T/F - The range and the standard deviation, are both measures of distance
T
T/F - To calculate the variance for a sample, SS is divided by df = n - 1
T
T/F -For a distribution with one or two extreme scores, the median is usually a more representative value than the mean.
T
For a particular sample, the largest distance (deviation) between a score and the mean is 11 points. The smallest distance between a score and the mean is 4 points. Therefore, the standard deviation _____. a. will be less than 4 b. will be between 4 and 11 c. will be greater than 11 d. It is impossible to say anything about the standard deviation.
b - between 4 and 11
Explain why it is necessary to have more than one standard procedure for defining and measuring central tendency.
because skewed results, certain scales/variables work better with certain measures
A set of N = 10 scores has a mean of µ = 50. If 20 points are added to one of the scores, what is the new value for the population mean? a. 50 b. 51 c. 52 d. 70
c - 52
A sample of n = 6 scores has a mean of M = 5. One person with a score of X = 12 is added to the distribution. What is the mean for the new set of scores? a. M = 5 b. M = 6 c. M = 7 d. M = 8
c - M = 7
Which of the following actions will always change the value of the mean? a. changing the value of one score b. adding a new score to the distribution c. removing a score from the distribution d. All 3 of the other choices are correct.
d - all 3 of the choices are correct
Using letter grades (A, B, C, D, and F) to classify student performance on an exam is an example of measurement on a(n) _______ scale of measurement
ordinal
T/F - a researcher reports that participants made fewer errors on a simulated air-traffic-control task when quiet background music was playing than when there was no music. For this study, the number of errors is the independent variable
false it's the dependent
σ (sigma)
population standard deviation
o2 - stands for
population variance
determining a person's reaction time would involve measurement on a(n) ______ scale of measurement
ratio
A set of 10 scores has SS = 90. If the scores are a sample, the sample variance is ____ and if the scores are a population, the population variance is ____.
s2 = 10, o2 = 9
s - stands for
sample standard deviation
s2 - stands for
sample variance
