# apu math302 quiz 4 done on may 2015

Question 1 of 20

1.0/ 1.0 Points

The null and alternative hypotheses divide all possibilities

into:

A.two sets that

overlap

B.two sets that may

or may not overlap

C.two non-overlapping sets

D.as many sets as

necessary to cover all possibilities

Question 2 of 20

1.0/ 1.0 Points

You conduct a hypothesis test and you observe values for the

sample mean and sample standard deviation when n = 25 that do not lead to the

rejection of H0. You calculate a p-value of 0.0667. What will happen to the

p-value if you observe the same sample mean and standard deviation for a sample

size larger than 25?

A.The p – value may

increase or decrease

B.The p – value decreases

C.The p – value stays

the same

D.The p – value

increases

Question 3 of 20

1.0/ 1.0 Points

A severe storm has an average peak wave height of 16.4 feet

for waves hitting the shore. Suppose that a storm is in progress with a severe

storm class rating. Let us say that we want to set up a statistical test to see

if the wave action (i.e., height) is dying down or getting worse. If you wanted

to test the hypothesis that the waves are dying down, what would you use for

the alternate hypothesis? Is the P-value area on the left, right, or on both

sides of the mean?

A.H1: f$mu f$ is greater than 16.4 feet; the P-value area

is on both sides of the mean

B.H1: f$mu f$ is less than 16.4 feet; the P-value area is

on the left of the mean

C.H1: f$mu f$ is greater than 16.4 feet; the P-value area

is on the left of the mean

D.H1: f$mu f$ is not equal to 16.4 feet; the P-value area

is on the right of the mean

Question 4 of 20

1.0/ 1.0 Points

A lab technician is

tested for her consistency by taking multiple measurements of cholesterol

levels from the same blood sample. The target accuracy is a variance in

measurements of 1.2 or less. If the lab technician takes 16 measurements and

the variance of the measurements in the sample is 2.2, does this provide enough

evidence to reject the claim that the lab technician’s accuracy is within the

target accuracy?

At the a = .01 level of significance, what is your

conclusion?

A.Cannot determine

B.Do not reject H0. At the f$alpha f$ = .01 level of significance there is not

sufficient evidence to suggest that this technician’s true variance is greater

than the target accuracy.

C.Reject H0. At the

f$alpha f$ = .01 level of significance,

there is enough evidence to support the claim that this technician’s variance

is larger than the target accuracy.

D.

Reject

H0. At the f$alpha f$ = .01 level of significance, there is not

enough evidence to support the claim that this technician’s true variance is

larger than the target accuracy.

Question 5 of 20

1.0/ 1.0 Points

A manufacturer of flashlight batteries took a sample of 13

batteries from a day’s production and used them continuously until they failed

to work. The life lengths of the batteries, in hours, until they failed were:

342, 426, 317, 545, 264, 451, 1049, 631, 512, 266, 492, 562, and 298.

At the .05 level of significance, is there evidence to

suggest that the mean life length of the batteries produced by this

manufacturer is more than 400 hours?

A.No, because the p-value for this test is

equal to .1164

B.Yes, because the

test value 1.257 is less than the critical value 2.179

C.No, because the

test value 1.257 is greater than the critical value 1.115

D.Yes, because the

test value 1.257 is less than the critical value 1.782

Question 6 of 20

1.0/ 1.0 Points

The hypothesis that an analyst is trying to prove is called

the:

A.quality of the

researcher

B.elective hypothesis

C.alternative hypothesis

D.level of

significance

Question 7 of 20

1.0/ 1.0 Points

Results from previous studies showed 79% of all high school

seniors from a certain city plan to attend college after graduation. A random

sample of 200 high school seniors from this city reveals that 162 plan to

attend college. Does this indicate that the percentage has increased from that

of previous studies? Test at the 5% level of significance.

What is your conclusion?

A.Reject H0. There is

enough evidence to support the claim that the proportion of students planning

to go to college is now greater than .79.

B.Do not reject H0. There is not enough

evidence to support the claim that the proportion of students planning to go to

college is greater than .79.

C.More seniors are

going to college

D.Cannot determine

Question 8 of 20

1.0/ 1.0 Points

The “Pizza Hot” manager commits a Type I error if he/she is

A.switching to new style when it is no better

than old style

B.staying with old

style when new style is no better than old style

C.staying with old

style when new style is better

D.switching to new

style when it is better than old style

Question 9 of 20

1.0/ 1.0 Points

Suppose that the mean time for a certain car to go from 0 to

60 miles per hour was 7.7 seconds. Suppose that you want to test the claim that

the average time to accelerate from 0 to 60 miles per hour is longer than 7.7

seconds. What would you use for the alternative hypothesis?

A.H1: f$mu f$ <
7.7 seconds
B.H1: f$mu f$ > 7.7 seconds

C.H1: f$mu f$ = 7.7 seconds

D.H1: f$mu geq f$

7.7 seconds

Question 10 of 20

1.0/ 1.0 Points

Which of the following values is not typically used for

f$alpha f$ ?

A.0.10

B.0.01

C.0.50

D.0.05

Question 11 of 20

1.0/ 1.0 Points

A null hypothesis can only be rejected at the 5%

significance level if and only if:

A.a 95% confidence interval does not include

the hypothesized value of the parameter

B.a 95% confidence

interval includes the hypothesized value of the parameter

C.the null hypothesis

is biased

D.the null hypotheses

includes sampling error

Part 2 of 3 – 4.0/

6.0 Points

Question 12 of 20

0.0/ 1.0 Points

Accepted characters: numbers, decimal point markers (period

or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000),

“E” or “e” (used in scientific notation). NOTE: For

scientific notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where

“a” and “b” need to have explicitly stated values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is

valid whereas {9i} is not.

A statistician wishes to test the claim that the standard

deviation of the weights of firemen is greater than 25 pounds. To do so, she

selected a random sample of 30 firemen and found s = 27.2 pounds.

Assuming that the weights of firemen are normally

distributed, if the statistician wanted to test her research hypothesis at the

.05 level of significance, what is the critical value?

Place your answer, rounded to 3 decimal places, in the

blank. For example, 23.456 would be a legitimate entry. 34.328

Question 13 of 20

1.0/ 1.0 Points

Accepted characters: numbers, decimal point markers (period

or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000),

“E” or “e” (used in scientific notation). NOTE: For

scientific notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where

“a” and “b” need to have explicitly stated values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is

valid whereas {9i} is not.

At a university, the average cost of books per student has

been $550 per student per semester. The Dean of Students believes that the

costs are increasing and that the average is now greater than $550. He surveys a sample of 40 students and finds

that for the most recent semester their average cost was $630 with a standard

deviation of $120. What is the test

value for this hypothesis test?

Test value: 4.22

Round your answer to two decimal places as necessary.

Question 14 of 20

1.0/ 1.0 Points

Accepted characters: numbers, decimal point markers (period

or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000),

“E” or “e” (used in scientific notation). NOTE: For

scientific notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where

“a” and “b” need to have explicitly stated values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is

valid whereas {9i} is not.

A survey determines that mint chocolate chip is the favorite

ice cream flavor of 6% of consumers. An ice cream shop determines that of 260

customers, 20 customers stated their preference for mint chocolate chip.

Find the P-value that would be used to determine if the

percentage of customers who prefer mint chocolate chip ice has increased at a

5% level of significance.

P-value: .1253 Round

your answer to four decimal places as necessary.

Question 15 of 20

1.0/ 1.0 Points

Accepted characters: numbers, decimal point markers (period

or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000),

“E” or “e” (used in scientific notation). NOTE: For

scientific notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where

“a” and “b” need to have explicitly stated values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is

valid whereas {9i} is not.

At a university, the average cost of books per student has

been $400 per student per semester. The Dean of Students believes that the

costs are increasing and that the average is now greater than $400. He surveys a sample of 40 students and finds

that for the most recent semester their average cost was $430 with a standard

deviation of $80. What is the test value

for this hypothesis test?

Test value: 2.37

Round your answer to two decimal places as necessary.

Question 16 of 20

1.0/ 1.0 Points

Accepted characters: numbers, decimal point markers (period

or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000),

“E” or “e” (used in scientific notation). NOTE: For

scientific notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where

“a” and “b” need to have explicitly stated values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is

valid whereas {9i} is not.

The ABC battery company claims that their batteries last at

least 100 hours, on average. Your experience with their batteries has been

somewhat different, so you decide to conduct a test to see if the company’s

claim is true. You believe that the mean life is actually less than the 100

hours the company claims. You decide to collect data on the average battery

life (in hours) of a random sample of n = 20 batteries. Some of the information

related to the hypothesis test is presented below.

Test of H0: f$mu geq

f$ 100 versus H1: f$mu< f$ 100
Sample mean 98.5
Std error of mean 0.777
Assuming the life length of batteries is normally
distributed, what is the p-value associated with this test? Place your answer,
rounded to 3 decimal places in the blank. For example, 0.234 would be a
legitimate entry. .034
Question 17 of 20
0.0/ 1.0 Points
Accepted characters: numbers, decimal point markers (period
or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000),
"E" or "e" (used in scientific notation). NOTE: For
scientific notation, a period MUST be used as the decimal point marker.
Complex numbers should be in the form (a + bi) where
"a" and "b" need to have explicitly stated values.
For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is
valid whereas {9i} is not.
Suppose a firm that produces light bulbs wants to know
whether it can say that its light bulbs typically last more than 1500 hours.
Hoping to find support for their claim, the firm collects a random sample of n
= 25 light bulbs and records the lifetime (in hours) of each bulb. The
information related to the hypothesis test is presented below.
Test of H0: f$mu leq f$
1500 versus H1: f$ mu f$ >

1500

Sample mean 1509.5

Std error of mean 4.854

Assuming the life length of this type of lightbulb is normally

distributed, what is the p-value associated with this test? Place your answer,

rounded to 3 decimal places in the blank. For example, .123 would be a

legitimate entry. 1.711

Part 3 of 3 – 2.0/

3.0 Points

Question 18 of 20

1.0/ 1.0 Points

The probability of making a Type I error and the level of

significance are the same.

True

False

Question 19 of 20

1.0/ 1.0 Points

In order to determine the p-value, it is unnecessary to know

the level of significance.

True

False

Question 20 of 20

0.0/ 1.0 Points

Using the confidence interval when conducting a two-tailed

test for the population mean, we do not reject the null hypothesis if the

hypothesized value for f$mu f$ falls

between the lower and upper confidence limits.

In

True

False