BUS 503 Quiz 2 True or False If we

Unlock access to all the studying documents.

View Full Document

True or False: If we use the chi-square method of analysis to test for the difference

between proportions, we must assume that there are at least 5 observed frequencies in

each cell of the contingency table.

True or False: In inferential statistics, the standard error of the sample mean assesses

the uncertainty or error of estimation.

True or False: In calculating the standard error of the estimate, SYX = , there are n

– k – 1 degrees of freedom, where n is the sample size and k represents the number of

independent variables in the model.

TABLE 12-20

A filling machine at a local soft drinks company is calibrated to fill the cans at a mean

amount of 12 fluid ounces and a standard deviation of 0.5 ounces. The company wants

to test whether the standard deviation of the amount filled by the machine is 0.5 ounces.

A random sample of 15 cans filled by the machine reveals a standard deviation of 0.67

ounces.

True or False: Referring to Table 12-20, there is sufficient evidence to conclude that the

standard deviation of the amount filled by the machine is not exactly 0.5 ounces when

using a 5% level of significance.

True or False: The smaller the p-value, the stronger the evidence is against the null

hypothesis.

True or False: Given below is the scatter plot of the market value (thousands$) and

profit (thousands$) of 50 U.S. companies. There appears to be a negative relationship

between market value and profit.

True or False: TABLE 17-10

Given below are results from the regression analysis where the dependent variable is

the number of weeks a worker is unemployed due to a layoff (Unemploy) and the

independent variables are the age of the worker (Age), the number of years of education

received (Edu), the number of years at the previous job (Job Yr), a dummy variable for

marital status (Married: 1 = married, 0 = otherwise), a dummy variable for head of

household (Head: 1 = yes, 0 = no) and a dummy variable for management position

(Manager: 1 = yes, 0 = no). We shall call this Model 1. The coefficient of partial

determination ( ) of each of the 6 predictors are, respectively,

0.2807, 0.0386, 0.0317, 0.0141, 0.0958, and 0.1201.

Model 2 is the regression analysis where the dependent variable is Unemploy and the

independent variables are Age and Manager. The results of the regression analysis are

given below:

Referring to Table 17-10, Model 1, there is sufficient evidence that the number of

weeks a worker is unemployed due to a layoff depends on at least one of the

explanatory variables at a 10% level of significance.

TABLE 11-3

As part of an evaluation program, a sporting goods retailer wanted to compare the

downhill coasting speeds of 4 brands of bicycles. She took 3 of each brand and

determined their maximum downhill speeds. The results are presented in miles per hour

in the table below.

True or False: Referring to Table 11-3, the null hypothesis should be rejected at a 5%

level of significance.

TABLE 11-8

An important factor in selecting database software is the time required for a user to

learn how to use the system. To evaluate three potential brands (A, B and C) of database

software, a company designed a test involving five different employees. To reduce

variability due to differences among employees, each of the five employees is trained

on each of the three different brands. The amount of time (in hours) needed to learn

each of the three different brands is given below:

Below is the Excel output for the randomized block design:

True or False: Referring to Table 11-8, the null hypothesis for the F test for the block

effects should be rejected at a 0.05 level of significance.

In a one-way ANOVA,

A) an interaction term is present.

B) an interaction effect can be tested.

C) there is no interaction term.

D) the interaction term has (c – 1) (n – 1) degrees of freedom.

An agronomist wants to compare the crop yield of 3 varieties of chickpea seeds. She

plants all 3 varieties of the seeds on each of 5 different patches of fields. She then

measures the crop yield in bushels per acre. Which of the following tests will be the

most appropriate to find out if the different patches is advantageous in reducing the

random error?

A) One-way ANOVA F test for differences among more than two means

B) Randomized block F test for differences among more than two means

C) Randomized block F test for block effect

D) Two-way ANOVA F test for the variety effect

TABLE 10-3

A real estate company is interested in testing whether the mean time that families in

Gotham have been living in their current homes is less than families in Metropolis.

Assume that the two population variances are equal. A random sample of 100 families

from Gotham and a random sample of 150 families in Metropolis yield the following

data on length of residence in current homes.

Gotham: G = 35 months, = 900 Metropolis: M = 50 months, = 1050

Referring to Table 10-3, what is(are) the critical value(s) of the relevant hypothesis test

if the level of significance is 0.01?

A) t Z = -1.96

B) t Z = 1.96

C) t Z = -2.080

D) t Z = -2.33

A study is under way in Yosemite National Forest to determine the adult height of

American pine trees. Specifically, the study is attempting to determine what factors aid

a tree in reaching heights greater than 60 feet tall. It is estimated that the forest contains

25,000 adult American pines. The study involves collecting heights from 250 randomly

selected adult American pine trees and analyzing the results. Identify the population

from which the study was sampled.

A) the 250 randomly selected adult American pine trees

B) the 25,000 adult American pine trees in the forest

C) all the adult American pine trees taller than 60 feet

D) all American pine trees, of any age, in the forest

TABLE 10-7

A buyer for a manufacturing plant suspects that his primary supplier of raw materials is

overcharging. In order to determine if his suspicion is correct, he contacts a second

supplier and asks for the prices on various identical materials. He wants to compare

these prices with those of his primary supplier. The data collected is presented in the

table below, with some summary statistics presented (all of these might not be

necessary to answer the questions which follow). The buyer believes that the

differences are normally distributed and will use this sample to perform an appropriate

test at a level of significance of 0.01.

Referring to Table 10-7, the buyer should decide that the primary supplier is

A) overcharging because there is strong evidence that this is the case.

B) overcharging because there is insufficient evidence to prove otherwise.

C) not overcharging because there is insufficient evidence to prove otherwise.

D) not overcharging because there is strong evidence to prove otherwise.

TABLE 10-5

To test the effectiveness of a business school preparation course, 8 students took a

general business test before and after the course. The results are given below.

Referring to Table 10-5, the number of degrees of freedom is

A) 14.

B) 13.

C) 8.

D) 7.

TABLE 18-3

A quality control analyst for a light bulb manufacturer is concerned that the time it takes

to produce a batch of light bulbs is too erratic. Accordingly, the analyst randomly

surveys 10 production periods each day for 14 days and records the sample mean and

range for each day.

Referring to Table 18-3, suppose the analyst constructs an R chart to see if the

variability in production times is in-control. What is the lower control limit for this R

chart?

A) 4.84

B) 3.37

C) 2.98

D) 1.34

Which of the following is a continuous quantitative (numerical) variable?

A) the color of a student’s eyes

B) the number of employees of an insurance company

C) the amount of milk in a 2-liter carton

D) the number of gallons of milk sold at the local grocery store yesterday

TABLE 17-1

A real estate builder wishes to determine how house size (House) is influenced by

family income (Income), family size (Size), and education of the head of household

(School). House size is measured in hundreds of square feet, income is measured in

thousands of dollars, and education is in years. The builder randomly selected 50

families and ran the multiple regression. Microsoft Excel output is provided below:

Referring to Table 17-1, what are the residual degrees of freedom that are missing from

the output?

A) 3

B) 46

C) 49

D) 50

Referring to Table 14-5, what is the p-value for testing whether Wages have a negative

impact on corporate sales?

TABLE 14-5

A microeconomist wants to determine how corporate sales are influenced by capital and

wage spending by companies. She proceeds to randomly select 26 large corporations

and record information in millions of dollars. The Microsoft Excel output below shows

results of this multiple regression.

A) 0.05

B) 0.0001

C) 0.00005

D) 0.99995

TABLE 17-10