Question

Find the critical t-value(s) for a one sample t-test given:

α = 0.05

df = 13

two-tailed test

Select one:
A. 2.160 and -2.160
B. 1.960 and -1.960
C. 2.375 and -2.375
D. 1.221
E. 2.639

Answer 1

sorry I dont know

Answer 2

sorry I dont know

Answer 3

sorry i cant help

Answer 4

You need to use a table of the t-distribution for this. Do you have that table?

Answer 5

In your question, the two-tail probability value is 0.05 and df = 13. So you need to go down the table to the row where df = 13 and across to the column where the two-tail probability value = 0.05. What is the value there?

Answer 6

Correct. You need to include the negative value of 2.160 in your answer as well as the positive value, the reason being it is a two-tail test.

Answer 7

If the sample size is n, we have n - 1 degrees of freedom. In your second question, what does df equal?

Answer 8

But I just explained how you can find the value of df. You just need to subtract 1 from the value given for n. Then you will have the value of df.
df = n - 1.
df = 17 - 1 = 16.

Answer 9

Correct. So put a negative sign before the value that you found in the table.

Answer 10

You are correct, the null hypothesis would be rejected in favor of the alternative hypothesis.

Answer 11

The p-value is greater than alpha. Therefore we fail to reject the null hypothesis.

Answer 12

Correct!

Answer 13

Sorry, I need to log out for a while. Will be back later, however :)

Answer 14

Later perhaps.

Answer 15

The test statistic (Z = 2.345) lies outside the rejection region. Therefore we retain the null hypothesis.

Answer 16

im sorry i dont know anything about this :[

Answer 17

I believe so... but don't take my word on it because I'm not very positive

Answer 18

2nd question?

Answer 19

i dont know anything about this sorry but let me tag someone who maybe can help @rebeccaxhawaii

Answer 20

I have no idea about the null hypothesis I'm sorry :(

Answer 21

What is it about?

Answer 22

sorry i don't know any of this @toxicsugar22

Answer 23

what do represent \[ \alpha \textrm{ and df } ?\]

Answer 24

a is allpha and df is degrees of freedom

Answer 25

@sugarapples @song_of_the_sole @FFASinger @Vestran01 @mayliz @ILovePuppiesLol @mathwizzard3

Answer 26

@urkhada

Answer 27

@phi @matlee @mathstudent55

Answer 28

@DanJS @Directrix

Answer 29

Investigators are interested in whether a new diet lowers total cholesterol in a group of individuals. They take a sample of 31 participants on the new diet. They know that the mean cholesterol level of the general population (µ) is 200 mg/dL, but they do not have information on the standard deviation of the population. The mean total cholesterol level in their sample of participants is 196 mg/dL and their sample has a standard deviation of 8 mg/dL.

Your research question of interest is:

Does the population of people on a new diet have a different mean cholesterol level than the general population?

You will use the information above for several of the following questions.



Which of the following represents the appropriate null hypothesis (H0), given this research question of interest?

Select one:
A. H0: µ ≠ 200
B. H0: µ = 200
C. H0: µ < 200
D. H0: µ = 196
E. H0: x̄ = 196

Answer 30

@pphalke

Answer 31

@ganeshie8 @phi @mathstudent55 @matlee