In: Statistics and Probability
PLEASE SHOW WORKING SOLUTION
13. Previous research states, "no evidence currently exists supporting or refuting the use of electric fans during heat waves" in terms of mortality and illness. Counterintuitively, Public Health guidelines suggest not using fans during hot weather, with some research reporting the potential of fans accelerating body heating.
You decide to research further this seemingly contradictory guidance, hypothesizing that the true population average core body temperature amidst higher ambient temperature and humidity levels while using an electric fan is different than 90.1 degrees Fahrenheit (°F) and you set the level of significance at 2.5% for your formal hypothesis test. You randomly sample 50 participants based on your research funding and for 45 minutes, the study participants sit in a chamber maintained at a temperature of 108°F (i.e., 42 degrees Celsius) and a relative humidity of 70%. After the first 45 minute warming period, for each participant you place a personal sized electric fan 3 feet away with its airflow directed at a given participant's chest area, and the participants relax in this position for the next 45 minutes. At the end of this 45minute fan period, you record the core body temperature of all participants. The following table comprises the data you collect.
Subject |
Core Body |
1 |
108.8 |
2 |
109.0 |
3 |
110.3 |
4 |
108.6 |
5 |
110.3 |
6 |
109.0 |
7 |
107.7 |
8 |
109.1 |
9 |
107.9 |
10 |
108.7 |
11 |
108.1 |
12 |
109.3 |
13 |
109.6 |
14 |
109.5 |
15 |
109.3 |
16 |
109.9 |
17 |
108.6 |
18 |
110.3 |
19 |
109.5 |
20 |
108.9 |
21 |
108.5 |
22 |
110.0 |
23 |
110.5 |
24 |
110.0 |
25 |
108.6 |
26 |
109.9 |
27 |
110.4 |
28 |
110.9 |
29 |
109.7 |
30 |
108.2 |
31 |
108.8 |
32 |
109.7 |
33 |
108.6 |
34 |
109.8 |
35 |
111.4 |
36 |
109.0 |
37 |
108.8 |
38 |
109.1 |
39 |
108.9 |
40 |
108.1 |
41 |
108.3 |
42 |
109.8 |
43 |
110.4 |
44 |
110.9 |
45 |
107.9 |
46 |
111.6 |
47 |
109.5 |
48 |
109.1 |
49 |
108.7 |
50 |
109.2 |
Per Step 3 of the 5-Steps to Hypothesis Testing, choose the appropriate decision rule.
Select one:
a. Reject H0 if z = +2.576 and z > -2.241
b. Reject H0 if t = -1.960 and t < -1.960
c. Accept H1 if z ≤ -1.645 or t ≥ +1.645
d. Reject H0 if z ≤ -2.241 or z ≥ +2.241
d. Reject H0 if z ≤ -2.241 or z ≥ +2.241
Level of Significance , α = 0.025
Tail = 2
critical z value, z* = ± 2.2414 [Excel formula =NORMSINV(α/no. of tails) ]
Ho : µ = 90.1
Ha : µ ╪ 90.1
(Two tail test)
Level of Significance , α =
0.03
population std dev , σ =
0.9115
Sample Size , n = 50
Sample Mean, x̅ = ΣX/n =
109.3340
Standard Error , SE = σ/√n = 0.9115 / √
50 = 0.1289
Z-test statistic= (x̅ - µ )/SE = ( 109.334
- 90.1 ) / 0.1289
= 149.21
critical z value, z* = ± 2.2414
[Excel formula =NORMSINV(α/no. of tails) ]
p-Value = 0.0000 [ Excel
formula =NORMSDIST(z) ]
Decision: p-value<α, Reject null hypothesis
THANKS
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