Question

An evolutionary psychologist hypothesizes that people will increase from the standard 24-hour sleeping and walking cycle if not exposed to the usual pattern of sunlight. To test this notion, a sample of volunteers were placed (individually) in a room in which there was no outside sunlight, no clocks, and other indications of time. They stayed in the room for a month and could turn the lights on and off as they pleased. What can the psychologist conclude with α = 0.01? The data are below.

id	cycle
12 6 8 1 3 14 5 7 4 17 2	22.9 25.1 24.9 20.8 21.8 22.8 23.9 22.8 20.8 24.9 22.9

a) What is the appropriate test statistic?
---Select--- na z-test One-Sample t-test Independent-Samples t-test Related-Samples t-test

b)
Population:
---Select--- the volunteers 24-hour cycle no outside sunlight lights on lights off
Sample:
---Select--- the volunteers 24-hour cycle no outside sunlight lights on lights off

c) Compute the appropriate test statistic(s) to make a decision about H₀.
(Hint: Make sure to write down the null and alternative hypotheses to help solve the problem.)
p-value =  ; Decision:  ---Select--- Reject H0 Fail to reject H0

d) compute the corresponding effect size(s) and indicate magnitude(s).
If not appropriate, input and/or select "na" below.
d =  ;   ---Select--- na trivial effect small effect medium effect large effect
r² =  ;   ---Select--- na trivial effect small effect medium effect large effect

e) Make an interpretation based on the results.

People significantly increase from the 24-hour sleeping and walking cycle if not exposed to the usual pattern of sunlight.

People significantly decrease from the 24-hour sleeping and walking cycle if not exposed to the usual pattern of sunlight.    

People do not significantly change from the 24-hour sleeping and walking cycle if not exposed to the usual pattern of sunlight.

Answer 1

a)

Here we have one sample so single sample t test will be used.

b)

Population: All people

Sample: the volunteers 24-hour cycle no outside sunlight lights on and lights off

c)

First we need to find the mean and SD of the sample. Following table shows the calculations:

	X	(X-mean)^2
	22.9	0.0225
	25.1	4.2025
	24.9	3.4225
	20.8	5.0625
	21.8	1.5625
	22.8	0.0625
	23.9	0.7225
	22.8	0.0625
	20.8	5.0625
	24.9	3.4225
	22.9	0.0225
Total	253.6	23.6275

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d)

It is large effect size.

Effect size r2 is

It is medium effect size.

e)

People do not significantly change from the 24-hour sleeping and walking cycle if not exposed to the usual pattern of sunlight.