SOCI 3307

Using Appendix A in your text, what Z values mark the limits of the middle 75.40% of the area or cases under the normal curve?

+/- 1.16

A Z score is:

-a point along the base line of the normal curve -the ratio of the difference between a score and the mean, divided by the standard deviation

Using Appendix A in your text, what percentage of area or cases under the normal curve will be found between the mean and a Z value of - 2.20?

.4861

In the normal curve, the value of the mean is:

0

The sum of the deviations from or about the mean will always equal:

0

Assume the test scores in your statistics class are normally distributed with a mean of 84 with a standard deviation of 4. Let's say you scored an 88 on the test. How many standard deviations are you above the mean?

1

In the normal curve, the value of the standard deviation is:

1

How much area under the normal curve is found beyond the Z values of +/- 2.58?

1%

A statement as to the approximate amount of area under a normal curve that is found between +/-1, +/-2, +/-3 standard deviations from the mean is known as the:

1-2-3 rule

The mean score for physics test scores is 72, with a standard deviation of 4. Your score on the test is 80. How many standard deviations above the mean is your test score?

2

Assume you took the a specialized entrance test and scored a 950. The mean test score was 800 and the standard deviation is 50. How many standard deviations is your score above the mean test score?

3

A sample of n=225 scores has x =103 and s2 = 16. What is the sample standard deviation?

4 (the missing symbols in the question are X = 103 and S2 = 16)

How much area under the normal curve is found beyond the Z values of +/- 1.96?

5%

What is the position of the median in the following distribution? {1, 4, 5, 7, 12, 14, 1, 13, 9, 10}

5.5th score

Assume you are working with population of N= 16 scores. The sum of all of the scores is equal to 96. What is the population mean?

6

What is the mode for the following distribution? {72, 83, 91, 72, 64, 93}

72

What is the value of the median in the following distribution? {1, 4, 5, 7, 12, 14, 1, 13, 9, 10}

8

A population of N=400 scores has μ = 25 and σ = 9. What is the population variance?

81 the missing symbols in the question are μ = 25 and σ = 9)

The Z values of +/- 1.96 encompass what percentage of area under the normal curve?

95%

The Z values of +/- 2.58 encompass what percentage of area under the normal curve?

99%

Which of the following is true?

A normal distribution is empirical and the normal distribution is theoretical

Which of the following reflects the interval or interval/ratio level of measurement?

A student's grade point average

According to the 1-2-3 rule, what percentage of area under a normal curve is found within 1 standard deviation above and below the mean?

Approximately 68%

According to the 1-2-3 rule, what percentage of area under a normal curve is found within 2 standard deviation above and below the mean?

Approximately 95%

According to the 1-2-3 rule, what percentage of area under a normal curve is found within 3 standard deviation above and below the mean?

Approximately 99%

Assume you had the following information regarding three different tests that you took: The math test mean was 70; the standard deviation was 5; your score was 65. The verbal test mean was 60 the standard deviation was 2; your score was 64. The science test mean was 80; the standard deviation was 3; your score was 83. On which test did you have your worst performance (relative to the other tests)?

Math

What is the simplest, most fundamental level of measurement?

Nominal

Students are given grades of A, B, C, D, or F on their homework assignments. The use of letter grades would be an example of what level of measurement?

Ordinal

Which of the following is NOT a measure of central tendency?

The average deviation

Which of the following is NOT a measure of dispersion?

The median

Which of the following correctly states the relationship between the standard deviation and the variance?

The variance is equal to the standard deviation, squared

Assume you had the following information regarding three different tests that you took: The math test mean was 70; the standard deviation was 5; your score was 65. The verbal test mean was 60 the standard deviation was 2; your score was 64. The science test mean was 80; the standard deviation was 3; your score was 83. On which test did you have your best performance (relative to the other tests)?

Verbal

Which of the following Z score values represents the location closest to the mean?

Z = +.50

Which of the following Z scores represents the mean?

Z = 0

A parameter is:

a characteristic of a population

A measure that summarizes a distribution in terms of its centrality or typicality is: ________ .

a measure of central tendency

A statistic is to a sample as:

a parameter is to a population

A sample is:

a portion of a population

The range is:

a statement of the lowest and the highest score in the distribution.

The normal curve/distribution is:

a symmetrical distribution

The normal curve/distribution is based upon:

an infinite number of cases

The measure of dispersion that is based upon absolute values of deviations from the mean is the:

average or mean deviation

A distribution with two modes is referred to as a:

bimodal distribution

Statistics that are used to summarize data are referred to as:

descriptive statistics

A symmetrical distribution is a distribution shaped in such a fashion that:

each half of the distribution is a mirror image of the other half

A table or listing that shows values and how many times each value occurs is:

frequency distribution

The scale of measurement that assumes there is an underlying scale of equal units, but without an absolute zero point, is the ________ scale of measurement.

interval

Inferential statistics are used to:

make statements about a population based on information from a sample

The ________ is found by calculating the sum of all of the scores in a distribution and then dividing the sum by the number of scores in the distribution.

mean

The measure of central tendency that is sensitive to extreme scores is the:

mean

X with a line over it is the symbol that represents:

mean of a sample

μ is the symbol that represents the:

mean of the population

The score that is located in the middle of a distribution or the score that cuts a distribution in half is the:

median

In order to obtain a more accurate reflection of the standard deviation or variance of the population, the standard deviation and variance for a sample are calculated by using ________ in the denominator of the formula, as opposed to using ________ in the formula.

n-1; n

A researcher wants to know how many emails senior citizens send to friends each week. If it were possible to find the average for the entire population of senior citizens, it would be an example of a ________ .

parameter

The average IQ score for the entire population of students enrolled at a local community college would be an example of a ________ .

parameter

The point at which a normal curve begins to change direction and the point located one standard deviation above and below the mean is referred to as the:

point of inflection

The marketing director of a company wants to conduct research on the buying habits of the company's customer base. The entire group of customers would be an example of a(n) ________ .

population

The term used to describe all possible cases is:

population

Researchers generally want to be able to generalize their results to a ________ , but to do so, they typically carry out their research on the basis of a ________ .

population, sample

One way to think about a Z score is to think of it as the:

ratio of the difference between a particular score and the mean of the distribution to the standard deviation of the distribution

Determining a person's level of education by asking him/her to indicate the number of school years completed would involve measurement on a(n) ________ level of measurement.

ratio or interval

The symbol used for standard deviation of a sample is:

s

The symbol used for the variance of a sample is:

s^2

The marketing director of a company examines data collected from 125 customers and determines that customers spent an average of $274.55 in purchases from the company over the past 12 months. The collection or group of 125 customers would represent a:

sample

A unimodal distribution that departs from symmetry, in the sense that most of the cases are concentrated at one end of the distribution is referred to as a(n):

skewed distribution

A skewed distribution that has most of the cases on the right side of the curve and a few extreme scores on the left side of the curve would be a(n)

skewed distribution with a negative skew

A skewed distribution that has most of the cases on the left side of the curve and a few extreme scores on the right side of the curve would be a(n)

skewed distribution with a positive skew

A researcher records the grade point average (GPA) at the end of the semester for each student in a sample of 50 freshman students. The average of the 50 GPA scores would be a:

statistic

Descriptive statistics are used to:

summarize or describe data

A distribution in which the two halves are mirror images of each other is referred to as a(n):

symmetrical distribution

In a skewed distribution, the elongated portion of the curve is referred to as:

the tail of the distribution

The normal curve/distribution is a(n)

theoretical curve/distribution

Which of the following Z scores is the farthest from the mean?

z = - 2.00

The symbol used for standard deviation of a population is:

σ

The symbol used for the variance of a population is:

σ2