How do I find the population mean (not the sample mean) in order to solve for t? (Second page)

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How do I find the population mean (not the sample mean) in order to solve for t? (Second page)
Name
Independent Samples t-test
1.
The owner of the Shine Company, which manufactures cleaning supplies, suspected that adding
a fragrance to a window cleaner leads people to believe that it cleans better than an unscented
product. The company selected 24 participants and randomly assigned 12 of them to the
scented cleaner and 12 to the unscented cleaner. They had each use it to clean a set of
windows and then complete a survey on how well the cleaner worked. The survey yielded a
numerical value, the "cleaning index," with higher numbers indicating better cleaning.
a.
State the nondirectional null hypothesis in symbols
Hscented
Hunscented
or
Hscented - Hunscented 0
b. State the nondirectional alternative hypothesis in symbols.
Hscented Hunscented
or
Hscented - Hunscented
c. Using an alpha level of .05 and a two-tailed test, what is the critical value of t?
2.069
d. Below are the data. Calculate the value of t. I will take you through it step by step.
Unscented
Scented
6
4
9
9
7
7
5
6
6
6
6
7
9
8
7
8
M = 6
SS = 14
S= 1.13
n = 12
M= 7,5
SS = 27
S= 1.57
n= 12
First, you must calculate the pooled variance: IF YOUR ANSWER IS 1.86 – CONGRATULATIONS!
14+27
ニ
Il +l
Now, calculate the estimated standard error: IF YOUR ANSWER IS 0.557 - CONGRATULATIONS!
1.86
1,86
31
= 0.55670.557
%3D
12
12
Transcribed Image Text:Name Independent Samples t-test 1. The owner of the Shine Company, which manufactures cleaning supplies, suspected that adding a fragrance to a window cleaner leads people to believe that it cleans better than an unscented product. The company selected 24 participants and randomly assigned 12 of them to the scented cleaner and 12 to the unscented cleaner. They had each use it to clean a set of windows and then complete a survey on how well the cleaner worked. The survey yielded a numerical value, the "cleaning index," with higher numbers indicating better cleaning. a. State the nondirectional null hypothesis in symbols Hscented Hunscented or Hscented - Hunscented 0 b. State the nondirectional alternative hypothesis in symbols. Hscented Hunscented or Hscented - Hunscented c. Using an alpha level of .05 and a two-tailed test, what is the critical value of t? 2.069 d. Below are the data. Calculate the value of t. I will take you through it step by step. Unscented Scented 6 4 9 9 7 7 5 6 6 6 6 7 9 8 7 8 M = 6 SS = 14 S= 1.13 n = 12 M= 7,5 SS = 27 S= 1.57 n= 12 First, you must calculate the pooled variance: IF YOUR ANSWER IS 1.86 – CONGRATULATIONS! 14+27 ニ Il +l Now, calculate the estimated standard error: IF YOUR ANSWER IS 0.557 - CONGRATULATIONS! 1.86 1,86 31 = 0.55670.557 %3D 12 12
Finally, calculate the t value: IF YOUR ANSWER IS 2.69 - CONGRATULATIONS!
(6-7,5)-(
0,557
e. Do you reject the null hypothesis? (Circle one)
YES
NO
f.
Based on these data, which of the following is true? (Check one)
O windows cleaned with the scented product were rated as cleaner than the windows
cleaned with the unscented product.
O windows cleaned with the unscented product were rated as cleaner than the
windows cleaned with the scented product.
O There was no significant difference in the "cleaning index" between windows cleaned
with the scented product and windows cleaned with the unscented product.
g. State your results as if you were writing them for a journal.
tL
P_.05, two-tailed
h. Calculate the effect size using the estimated d. Is this a small, medium, or large effect?
IF YOUR ANSWER IS 1.09 - CONGRATULATIONS!
i.
Now state the directional null hypothesis in symbols.
Hscented
Hunscented
j. State the directional alternative hypothesis in symbols.
Hscented Hunscented
k. What is the critical value of t in this case? Assume the alpha level is still.05.
Would your conclusion about rejecting the null hypothesis change with a one-tailed
test? Circle one:
I.
YES
NO
Adapted from: Steinberg, W.J. (2008). Statistics Alive! Thousand Oaks, CA: Sage.
Transcribed Image Text:Finally, calculate the t value: IF YOUR ANSWER IS 2.69 - CONGRATULATIONS! (6-7,5)-( 0,557 e. Do you reject the null hypothesis? (Circle one) YES NO f. Based on these data, which of the following is true? (Check one) O windows cleaned with the scented product were rated as cleaner than the windows cleaned with the unscented product. O windows cleaned with the unscented product were rated as cleaner than the windows cleaned with the scented product. O There was no significant difference in the "cleaning index" between windows cleaned with the scented product and windows cleaned with the unscented product. g. State your results as if you were writing them for a journal. tL P_.05, two-tailed h. Calculate the effect size using the estimated d. Is this a small, medium, or large effect? IF YOUR ANSWER IS 1.09 - CONGRATULATIONS! i. Now state the directional null hypothesis in symbols. Hscented Hunscented j. State the directional alternative hypothesis in symbols. Hscented Hunscented k. What is the critical value of t in this case? Assume the alpha level is still.05. Would your conclusion about rejecting the null hypothesis change with a one-tailed test? Circle one: I. YES NO Adapted from: Steinberg, W.J. (2008). Statistics Alive! Thousand Oaks, CA: Sage.
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