Statistics: Statistics: Informed Decision Using Data Math 1342 Flashcards

School administrators collect data on students attending the school. Which of the following variables is quantitative?

a) class( freshman, soph., jr, sr.)

b) whether the student has taken the SAT

c) whether the student is in honors courses

d) Grade Point Average

e) none of these

the colors of book covers on a bookshelf
A) qualitative B) quantitative

the number of calls received at a companyʹs help desk
A) quantitative B) qualitative

the number of seats in a school auditorium
A) quantitative B) qualitative

the numbers on the shirts of a boyʹs football team
A) qualitative B) quantitative

the bank account numbers of the students in a class
A) qualitative B) quantitative

The average age of 120 employees of a large company was found to be 37.4 years. Classify the value of 37.4 years of age.
a) The value 37.4 years of age is a parameter.
b) The value 37.4 years of age is a both a statistic and a parameter.
c) The value of 34.7 years of age is a statistic.
d) The value of 37.4 years of age is neither a statistic nor a parameter.
e) none of these

A college had 14 dorms each with 4 floors. A researcher numbered the floors from 1 through 46 and randomly selected 5 floors. He administered his research instrument to each resident of the five selected dorm-floors. Identify the sampling technique.
a) simple random sample

b) cluster sample

c) stratified sample

d) systematic sample

Thirty-five math majors, 33 music majors and 45 history majors are randomly selected from 251 math majors,
518 music majors and 332 history majors at the state university. What sampling technique is used?
A) stratified
B) simple random
C) cluster
D) convenience
E) systematic

Every fifth adult entering an airport is checked for extra security screening. What sampling technique is used?
A) systematic
B) simple random
C) cluster
D) convenience
E) stratified

A lobbyist for the oil industry assigns a number to each senator and then uses a computer to randomly
generate ten numbers. The lobbyist contacts the senators corresponding to these numbers. What sampling
technique was used?
A) simple random
B) convenience
C) cluster
D) stratified
E) systematic

A statistics student interviews everyone in his apartment building to determine who owns a cell phone. What
sampling technique is used?
A) convenience
B) simple random
C) cluster
D) systematic
E) stratified

The average age of 120 employees of a large company was found to be 37.4 years. Classify the group of 120 employees.
a) The group of 120 employees is a population in this study.
b) The group of 120 employees is a sample in this study.
c) The group of 120 employees is a parameter in the study.
d) The group of 120 employees is a statistics in this study.
e) none of these.

A marketing firm did a survey to determine how many people use a product. Of the one hundred people contacted, 15 said they used the product. What type of study is this?
a) Observational

b) Experimental

c) Neither

A medical researcher obtains a sample of adults suffering from diabetes. She randomly assigns 30 people to a
treatment group and 30 to a placebo group. The treatment group receives a medication over a period of three
months and the placebo group receives a placebo over the same time frame. At the end of three months the
patientsʹ symptoms are evaluated.
A) experiment B) observational study c) Neither

A poll is conducted in which professional musicians are asked their ages.
A) observational study B) experiment c) Neither

A scientist was studying the effects of a new fertilizer on crop yield. She randomly assigned half of the plots on
a farm to group one and the remaining plots to group two. On the plots in group one, the new fertilizer was
used for a year. On the plots in group two, the old fertilizer was used. At the end of the year the average crop
yield for the plots in group one was compared with the average crop yield for the plots in group two.
A) experiment B) observational study c) Neither

A statistics student wishes to test the strength of various brands of paper towel. He chooses 5 brands and selects 6 towels from each brand. He numbers them 1-30. He randomly selects a towel and places it in an embroidery hoop. Exactly 10 ml of water and a large weight are placed in the center of the towel. The time it takes for the towel to break is recorded. In this case the explanatory variable is the

a) amount of time it takes for the towel to break.
b) 10 ml of water and the large weight.
c) brand of paper towel
d) large weight.
e) number of paper towels used in this experiment.

The graph of a normal curve is given. Use the graph to identify the value of μ and σ.
a) μ = 137, σ = 6

b) μ = 18, σ= 137

c) μ = 137, σ = 18

d) μ = 6, σ = 137

The graph of a distribution of data shows that the graph is skewed to the right then the
a) Mean < Median

b) Mean = Median

c) Mean > Median

d) No conclusion can be made without inspecting the data first.

Last year, nine employees of an electronics company retired. Their ages at retirement are listed below. Find the mean retirement age.
Age
/53/67/68/50/62/58/63/52/57

a) 58 years

b) 58.9 years

c) 57.6 years

d) 58.2 years

e) 62

How do calculate the mean using the T-84 calculator?

The stem-and-leaf plot shows the results of a mathematics test for 30 students. What is the median score?
a) 81.5

b) 79

c) 87.5

d) 80.5

e) 86.5

At one college, GPA’s are normally distributed with a mean of 2.9 and a standard deviation of 0.6. What percentage of students at the college have a GPA between 2.3 and 3.5?

a) 68%

b) 99.7%

c) 95%

d) 84.13%

e) none of the

A relative frequency histogram for the sale prices of homes sold in one city during 2006 is shown below.
Describe the shape of the distribution
a) symmetric

b) right skewed

c) left skewed

d) uniform

The test scores for 15 students are listed below. Identify any potential outliers.

a) 33

b) 33,43

c) 33, 99

d) there are no outliers

You have collected some data. After calculating your measures of central tendency, you have found the
μ = 80.2 and the median is also 80.2 Which of the following would BEST describe the shape of the histogram.

a) positively skewed

b) negatively skewed

c) symmetric

The term test scores of 15 students enrolled in a Introductory Statistics class were recorded in ascending order as follow:
4, 7, 7, 9, 10, 11, 13, 15, 15, 15, 17, 18, 19, 19, 19, 20
What number represents the 30th percentile for this data?
a) 7 b) 10 c) 15 d) 18 e) none of these

The stem-and-leaf plot to the right summarizes the number of gold medals earned by 40 countries in the Winter Olympics for 1924-1998.
The data depicts a distribution that is

a) skewed to the left

b) skewed to the right

c) symmetric

d) uniform e) not identifiable from the information given.

In a recent poll adults were asked to estimate the percentage of children who live in poverty in the United States. The mean response was 7% and the median was 12%. What does this suggest about the shape of the distribution of responses.
a) This distribution is most likely symmetric
b) The standard deviation of the distribution is .04
c) The distribution is most likely skewed to the left.
d) The distribution is most likely skewed to the right.
e) This is a uniformed distribution.

The boxplots to the right summarize two sets of data, A and B. Which of the following must be true?
I. Set B contains more observations than Set A.
II. Set A has a larger range than Set B.
III. Set A and Set B have the same median

a) I only

b) III only

c) I and II only

d) II and III only

e) I, II, and III

A study was designed to investigate the effects of two variables—(1) a student’s level of mathematical anxiety and (2) teaching method—on a student’s achievement in a math course. Students who had a low level of math anxiety were taught using the traditional expository method. These students obtained a mean of 270 with a standard deviation of 30 on a standardized test. Assuming a bell-shaped distribution, where would approximately 95% of the students score?
a) between 180 and 360

b) between 210 and 330

c) below 180 or above 360

d) below 210 or above 330

Which of the following is not a principle of design?
a) control

b) comparison

c) replication

d) randomization

e) All of these are principles of design.

Twenty men and 20 women with migraine headaches were subjects in an experiment to determine the effectiveness of a new pain medication. Ten of the 20 men and 10 of the 20 women were chosen at random to receive the new drug. The remaining 10 men and 10 women received a placebo. The decrease in pain was measure for each subject. The design of this experiment is
a) completely randomized with one factor, gender
b) completely, randomized with one factor, drug
c) randomized block, blocked by drug and gender
d) randomized block, blocked by gender
e) randomized block, blocked by drug

In a certain southwestern city the air pollution index averages 62.5 during the year with a standard deviation of 18. Assuming that the empirical rule is appropriate, the index falls within what interval 95% of the time?

A) (8.5, 116.5)

B) (45.4, 79.6)

C) (26.5, 98.5)

D) (44.5, 80.5)

E) Not enough info.

When a set of data has suspect outliers, which of the following are preferred measures of central tendency and of variability?
a) mean and standard deviation

b) mean and variance

c) mean and range
d) median and range

e) median and interquartile range

The test scores on the Chapter 7 mathematics test have a mean of 66 and a standard deviation of 13. Andrea scored 89 on the test. How many standard deviations from the mean is her score?

a) 0.60 sd below the mean

b) 1.77 sd below the mean

c) 1.77 sd above the mean

d) 0.60 sd above the mean

_________ 31) Use the box-and-whisker plot below to determine which is accurate
a) About 25% of the adults have cholesterol levels of at most 211
b) about 75% of the adults have cholesterol levels less than 180.
c) One half of the cholesterol levels are between 180 and 197.5
d) One half of the cholesterol levels are between 180 and 211
e) The mean cholesterol level is 197.5

In statistics out of 100, marks of 21 students in final exams are as 90, 95, 95, 94, 90, 85, 84, 83, 85, 81, 92, 93, 82, 78, 79, 81, 80, 82, 85, 76, 85 then mode of data is

A) 85
B) 95
C) 90
D) 81