There Are 26 Questions on This Test Adding up to a Total of 104 Points. Read All the Questions

STP 226 Test 1

NAME:______ASU ID: ______

TU 9:15 – 10:30

STP 226 SPRING 2001

Exam 1

There are 26 questions on this test adding up to a total of 104 points. Read all the questions carefully.

Honor Policy: By signing below you confirm that you have neither given nor received any unauthorized assistance on this exam.

Signature: ______

Date: ______

Directions: Please read the questions carefully and place your answer in the space

provided at the end of each question.

1.Based on a random sample of 1000 people, a researcher obtained the following estimates of the percentage of people lacking health insurance in one U.S. city.

Age / Percentage not covered
18 – 24 / 28.2
25 – 39 / 24.9
40 – 54 / 19.1
55 – 65 / 16.5

Classify the study as either descriptive or inferential. ______

2.A manager determines the average age of his employees. Decide whether this study is descriptive or inferential. ______

3.A market researcher is conducting a telephone poll. She has a list of 581 registered voters and wishes to interview a random sample of 12 of them. Construct a list of 12 random numbers between 1 and 581 that can be used in obtaining the required simple random sample. Use the random number table at the end of this test and use as your starting point the digits 432 in row 13, columns 10–12. List all the random numbers that can be used to obtain the sample of 12 voters.

4.The finalists in an essay competition are Lisa (L), Melina (M), Ben (B), Danny (D), Eric (E), and Joan (J). Consider these finalists to be a population of interest. The possible samples (without replacement) of size two that can be obtained from this population of six finalists are as follows.

L,ML,BL,DL,EL,JM,BM,DM,EM,JB,DB,E B,J D,E D,J E,J

If a simple random sampling method is used to obtain a sample of two of the finalists, what are the chances of selecting Lisa and Danny? ______

5.At one hospital in 1992, 674 women were diagnosed with breast cancer. Five years later, 88% of the Caucasian women and 83% of the African American women were still alive. Identify this study as an observational study or as a designed experiment. ______

Use the following designed experiment to answer questions 6 – 10.

In a clinical trial, 780 participants suffering from high blood pressure were randomly assigned to one of three groups. Over a one-month period, the first group received a low dosage of an experimental drug, the second group received a high dosage of the experimental drug, and the third group received a placebo. The diastolic blood pressure of each participant was measured at the beginning and at the end of the period and the change in blood pressure was recorded.

6.Identify the experimental unit.______

7.Identify the response variable.______

8.Identify the factor.______

9.Identify the levels of the factor.______

10.Identify the treatments.______

Circle the letter of the best choice in numbers 11 to 14.

11.An education researcher randomly selects 38 schools from one school district and interviews all the teachers at each of the 38 schools. Identify the type of sampling used in this example.

a.Systematic random samplingb.Cluster sampling

c.Stratified samplingd.Simple random sampling

12.At a college there are 120 freshmen, 90 sophomores, 110 juniors, and 80 seniors. A school administrator selects a simple random sample of 12 of the freshmen, a simple random sample of 9 of the sophomores, a simple random sample of 11 of the juniors, and a simple random sample of 8 of the seniors. She then interviews all the students selected. Identify the type of sampling used in this example.

a.Simple random samplingb.Systematic random sampling

c.Cluster samplingd.Stratified sampling

13.From a group of 496 students, every 49th student starting with the 3rd student is selected. Identify the type of sampling used here.

a.Simple random samplingb.Cluster sampling

c.Systematic random samplingd.Stratified sampling

14.A pollster uses a computer to generate 500 numbers and then interviews the voters corresponding to those numbers. Identify the type of sampling used in this example.

a.Stratified samplingb.Simple random sampling

c.Systematic random samplingd.Cluster sampling

15.An agricultural researcher wishes to compare the yield of four different varieties of wheat. 64 plots of land are available for an experiment. On each plot of land one of the varieties of wheat will be grown. At the end of the experiment the yield for the different varieties will be compared. 32 of the plots are at one site (site A) and the other 32 are at another site (site B). The soil at site A differs significantly from the soil at site B. The researcher wishes to design an experiment. In this example, why might a randomized block design, with blocking by soil type, be preferable to a completely randomized design?

______

For numbers 16 and 17, identify the variables as either qualitative or quantitative.

16.A monthly electric bill (in dollars).______

17.Dennis has type O blood and Eve has type A blood.______

18.Construct a frequency distribution for the given qualitative data. The blood types of 20 people who agreed to participate in a medical study were as follows:

O / A / A / O / O / AB / O / B / A / O
A / O / A / B / O / O / O / AB / A / A

Use the following designed to answer questions 19 – 20.

A nurse measured the blood pressure of each person who visited her clinic. Following is a relative-frequency histogram for the systolic blood pressure readings for those people aged between 25 and 40. The blood pressure readings were given to the nearest whole number. Use the histogram to answer questions 18 and 19.

Relative

Frequency

Systolic Blood Pressure (mm Hg)

19.Approximately what percentage of the people aged 25 – 40 had a systolic blood pressure reading between 110 and 119 inclusive? ______

20.Approximately what percentage of the people aged 25 – 40 had a systolic blood pressure reading less than 120? ______

21.Construct a pie chart representing the given data set. 300 movie critics rated a movie. The following data give the rating distribution.

Rating / Frequency / Relative Frequency
Excellent / 60 / 0.20
Good / 150 / 0.50
Fair / 90 / 0.30

Questions 22, 23, and 24 are based on the following.

Identify the overall shape of the distribution as (roughly) bell-shaped, triangular, uniform, reverse J-shaped, J-shaped, right skewed, left skewed, bimodal, or multimodal.

22.A relative frequency histogram for the sale prices of homes sold in one city during 1996 is shown below.

Relative

Frequency

Sale Price of Home ($10,000s)______

23.The ages of a group of patients being treated at one hospital for osteoporosis are summarized in the frequency histogram below.

Frequency

Age of Patient______

24.A frequency histogram is given below for the weights of a sample of college students.

Frequency

Weight (Pounds)______

25.A machine is supposed to fill juice bottles with 16 fluid ounces of juice. The manufacturer picks a sample of bottles which have been filled by the machine and determines the volume of the juice in each bottle. The results are shown in the stem-and-leaf diagram below. The leaf unit is 0.1.

15 1

15 3

15 4 5

15 6 6 7 7 7 7

15 8 8 8 8 9 9 9 9 9

16 0 0 0 0 0 0 1 1 1 1 1

16 2 2 2 2 3 3 3 3

16 4 4 5

16 6 6

16 8

What is the smallest volume of juice (in fluid ounces) measured for the bottles sampled? ______

26.A population has a J-shaped distribution. Two different samples of size 12 are picked from the population. Two different samples of size 1000 are then picked from the population. Do you think that the distribution of the two samples of size 12 will have roughly the same shape? Do you think that the distribution of the two samples of size 1000 will roughly have the same shape? Explain your thinking.

______

STP 226 TEST 1 SPRING 2001