Midterm study for statistics

For a negatively skewed distribution with a mean of M = 20, what is the most probable value for the median?​ A. ​greater than 20 ​B. 20 C. ​less than 20 ​D. 0

​greater than 20

A researcher measures eye color for a sample of n = 50 people. Which measure of central tendency would be appropriate to summarize the measurements?​ ​mean ​median ​mode ​weighted mean

​mode

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

​mode, median, mean

What is the shape of the distribution for the following set of data?​ Scores: 1, 2, 3, 3, 4, 4, 4 5, 5, 5, 5, 6 ​symmetrical ​positively skewed ​negatively skewed ​cumulative

​negatively skewed

In the simplest experimental study, ____.​ 1. ​one variable is measured and two groups are compared 2. ​two variables are measured and two groups are compared ​3.one variable is measured and there is only one group of participants 4. ​two variables are measured and there is only one group of participants

​one variable is measured and two groups are compared

Determining the class standing (1st, 2nd, and so on) for the graduating seniors at a high school would involve measurement on a(n) ____ scale of measurement.​ ​nominal ​ordinal ​interval ​ratio

​ordinal

A researcher uses an anonymous survey to investigate the study habits of American college students. The entire group of American college students is an example of a ____.​ ​sample ​statistic ​population ​parameter

​population

​For which of the following correlations would the data points be clustered most closely around a straight line? ​r = -0.10 ​r = +0.40 ​r = -0.70 ​r = -0.00

​r = -0.70

Which of the following symbols identifies the sample variance?​ ​s ​s2 ​Σ ​σ2

​s2

A researcher uses an anonymous survey to investigate the study habits of American college students. Based on the set of 56 surveys that were completed and returned, the researcher finds that these students spend an average of 4.1 hours each week working on course material outside of class. For this study, the set of 56 students who returned surveys is an example of a ____.​ ​parameter ​statistic ​population ​sample

​sample

For the following frequency distribution of exam scores, what is the lowest possible reported score on the exam?​ X f 90-94 3 85-89 4 80-84 5 75-79 2 70-74 1 ​x = 70 ​x = 74 ​x = 90 ​x=94

​x = 70

Which of the following symbols identifies the population standard deviation?​ ​s ​s2 ​σ ​σ2

​σ

You have a score of X = 75 on a statistics exam. The mean score for the class on the exam is μ = 70. Which of the following values for the standard deviation would give you the highest position within the class?​ ​σ = 1 ​σ = 5 ​σ = 10 ​σ = 12

​σ = 1

Given a population with mean m = 60, which of the following values for the population standard deviation would cause X = 68 to have the most extreme position in the distribution?​ ​σ = 2 ​σ = 3 ​σ = 5 ​σ = 12

​σ = 2

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

2

A recent study reports that elementary school students who were given a nutritious breakfast each morning had higher test scores than students who did not receive the breakfast. For this study, what is the independent variable?​ 1. ​The students who were given the nutritious breakfast ​2.The students who were not given the nutritious breakfast 3. ​Whether or not a breakfast was given to the students ​4.The test scores for the students

3. ​Whether or not a breakfast was given to the students

What is the value of (ΣX)2 for the following scores?​ Scores: 1, 5, 2 ​10 ​16 ​30 ​64

64

What is the value of ΣX2 for the following scores?​ Scores: 1, 0, 2, 4 ​14 ​21 ​28 ​49

​21

For the following frequency distribution of exam scores, how many students had scores lower than X = 80?​ X f 90-94 3 85-89 4 80-84 5 75-79 2 70-74 1 ​2 ​3 ​7 ​8

​3

For a bell-shaped distribution with µ = 30, what is the most probable value for the mode?​ ​30 ​greater than 30 ​less than 30 ​0

​30

In a grouped frequency distribution one interval is listed as 50-59. Assuming that the scores are measuring a continuous variable, what are the real limits of this interval?​ ​50 and 59 ​50.5 and 59.5 ​49.5 and 59.5 ​49.5 and 60.5

​49.5 and 59.5

Which of the following statements is true for a distribution of data points?​ ​75% of the data points are above the median. ​50% of the scores are above the median. ​60% of the scores are below the median. ​95% of the data points are above the median.

​50% of the scores are above the median.

If a set of exam scores forms a symmetrical distribution, what can we conclude about the students' scores?​ ​Most of the students had relatively high scores. ​Most of the students had relatively low scores. ​About 50% of the students had high scores and the rest had low scores. ​It is not possible the draw any conclusions about the students' scores.

​About 50% of the students had high scores and the rest had low scores.

Which of the following statements is true for a distribution of scores?​ ​No score is exactly equal to the mean. ​No score is exactly equal to the median. ​At least one score is exactly equal to the mode. ​At least one score is equal to the median.

​At least one score is exactly equal to the mode.

Which of the following actions will always change the value of the mean?​ ​Changing the value of one score ​Adding a new score to the distribution ​Removing a score from the distribution ​Adding a score equal to the mean.

​Changing the value of one score

What is indicated by a positive value for a correlation?​ 1. ​Increases in X tend to be accompanied by increases in Y. 2. ​Increases in X tend to be accompanied by decreases in Y. ​3.A much stronger relationship exists than if the correlation were negative. ​4. A much weaker relationship exists than if the correlation were negative.

​Increases in X tend to be accompanied by increases in Y.

Which description provides an example of a discrete variable?​ 1. ​The time each student arrives in a psychology class 2. The gender of each student in a psychology class 3.The amount of time to solve a problem 4. ​The amount of weight gained for each freshman at a local college

​The gender of each student in a psychology class

What additional information is obtained by measuring two individuals on an interval scale compared to an ordinal scale?​ ​Whether the measurements are the same or different ​The direction of the difference ​The size of the difference ​Whether the measurement is numerical

​The size of the difference

In a frequency distribution graph, frequencies are presented on the ____ and the scores (categories) are listed on the ____.​ ​X axis; Y axis ​horizontal line; vertical line ​Y axis; X axis ​class interval ;horizontal line

​Y axis; X axis

The classrooms in the Psychology department are numbered from 100 to 108. A professor records the number of classes held in each room during the fall semester. If these values are presented in a frequency distribution graph, what kind of graph would be appropriate?​ ​a histogram ​a polygon ​a histogram or a polygon ​a bar graph

​a bar graph

A distribution with two modes is said to be:​ ​two modal ​minor modal ​bimodal ​main modal

​bimodal

Statistical methods that organize, summarize, or streamline data are called ____.​ ​parameters ​statistics ​descriptive statistics ​inferential statistics

​descriptive statistics