Stat 95

Joe has a job delivering pizza, and he wants to know more about his deliveries. On Wednesday, each time he delivers an order, he uses his trip odometer to find out the total number of miles he drives for that order. The miles per order (miles) are: 2.2, 3.4, 5.3, 2.1, 1.9 What was the standard deviation of this sample of deliveries?

1.42

In a sample of n = 6, five individuals all have scores of X = 10 and the sixth person has a score of X = 16. What is the mean for this sample?

11

Which set of scores has the smallest standard deviation?

145, 143, 145, 147

The variance for a sample is 328. What is the sample's standard deviation? Round to the nearest whole number.

18

Let's say you have this data: 25, 26, 24, 26, 25, 7, 6, 6, 15, 10, 25, 24, 26 What should your bin size be if you want to have 10 bins?

2

For a normal distribution with a mean of M = 20, the mode is ____.

20

A population of scores has a mean of 50 and standard deviation of 10. This population is normally distributed. Therefore, 95% of the scores in the distribution should fall between ____ and ____.

30 and 70

Compute the sum of squared deviations (SS) for the following scores: 91, 99, 83, 85, 76, 98, 22

4214.86

What is the value of the median for the following set of scores? Scores: 1, 3, 3, 5, 6, 7, 8, 23

5.5

A set of N = 20 exam scores has a mean of m = 50. The instructor discovered that an error was made grading one exam, so 20 points are added to that student's score. After adding the 20 points, what is the new mean for the class? Hint: Write down the formula for the mean and fill in all known information. What is the new mean for the class

51

Four scores from a statistics exam are reported as deviation scores. Which of these scores was the highest score?

8

Sam wants to know the number of hours that US college students work per week, so he asks his friends at San Jose State University to complete a survey. What is wrong with his approach?

His sample may not be representative of the population of US college students.

Which of the following statements qualifies as a hypothesis? Choose all that apply.

The more people who give an incorrect ansewr, the more likely you are to give the same incorrect answer. The number of people around you will influence the chances that you will help someone who needs it. The bigger the tax breaks for the rich, the more jobs will be created. The more hours of sleep you get, the better your memory for faces.

A researcher is interested in the sleeping habits of American college students. A group of 125 students is interviewed and the researcher finds that these students sleep an average of 6.2 hours per day. This average is an example of a:

statistic

Which of the following are variables? Choose all that apply.

Whether someone is alive or dead Scores on an intelligence test The number of friends people have on Facebook

In a population of N = 6, five of the individuals all have scores that are exactly 1 point above the mean. From this information you can determine that the score for the sixth individual must be ____.

below the mean

A variable that consists of indivisible categories with no other scores existing between neighboring categories is called a(n) ____ variable.

discrete

A professor recorded scores from a 5-point quiz (and fractional points were awarded) for each student in an introductory psychology class. If the data are presented in a frequency distribution graph, what type of graph should be used

histogram

An operational definition is used to ____ a hypothetical construct.

measure and define

Ranking a group of cities in terms of "quality of life" would be an example of measurement on a(n) ____ scale of measurement.

ordinal

A number that describes a population is called a:

parameter

Dr. Snycerski used an anonymous survey to investigate the alcohol use of all California residents. The entire group of California residents is an example of a(n):

population

A researcher is interested in the sleeping habits of American college students. A group of 125 students is interviewed and the researcher finds that these students sleep an average of 6.2 hours per day. For this study, the 125 students are an example of a:

sample

A researcher is interested in the sleeping habits of American college students. A group of 50 students is interviewed and the researcher finds that these students sleep an average of 6.7 hours per day. For this study, the 50 students are an example of a

sample

Researchers are trying to see if getting married makes couples happier than if they stay unmarried. They want to see if this is true for all adults in the United States. To test this, the researchers give a survey to 1000 married and unmarried adults in the United States. The 1000 participants are a:

sample

Although a research study is typically conducted with a relatively small group of participants known as a ____, most researchers hope to generalize their results to a much larger group know as a ____.

sample, population

The average verbal SAT score for the entire class of entering freshmen is 530. However, if you select a sample of 20 freshmen and compute their average verbal SAT score, you probably will not get exactly 530. What statistical concept is used to explain the natural difference that exists between a sample mean and the corresponding population mean?

sampling error

The average verbal SAT score for the entire class of entering freshmen is 530. However, if you select a sample of 80 freshmen and compute their average verbal SAT score, you probably will not get exactly 530. What statistical concept is used to explain the natural differences that exists between a sample mean and the corresponding population mean?

sampling error

graph more to one side

skewed

The variance of the scores in a sample tends to be ___ the variability of the scores in the population from which the sample was obtained.

smaller than

A number that describes a sample is called a:

statistic

A researcher is interested in the sleeping habits of American college students. A group of 50 students is interviewed and the researcher finds that these students sleep an average of 6.7 hours per day. For this study, the average of 6.7 hours is an example of a

statistic

A recent study reports that increased lighting during the winter months results in lower depression scores. For this study, what is the dependent variable?

the level of depression

Why compute the mean?

the mean tells you a typical or representative score in the distribution

A sample has a mean of M = 72. If one person with a score of X = 58 is removed from the sample, what effect will it have on the sample mean?

the sample mean will increase

In a normal shaped distribution, ____.

the scores pile up in the middle and taper off symmetrically to both sides.

A recent study reports that infant rats fed a special protein-enriched diet reached an adult weight 10 percent greater than litter-mates raised on a regular diet. For this study, what is the independent variable

the type of diet given to the rats