In: Statistics and Probability
A nurse at a health clinic wanted to see if its ear thermometers
and oral thermometers measure the same body temperature. The nurse
selects a sample of healthy staff members and took the temperature
of each with both thermometers. The temperature data are below.
What can the nurse conclude with α = 0.01?
ear | oral |
---|---|
97.4 97.9 96.3 97.4 98.1 97.7 |
97.8 98.6 98.9 97.6 99.1 98.2 |
a) What is the appropriate test statistic?
---Select---naz-testOne-Sample t-testIndependent-Samples
t-testRelated-Samples t-test
b)
Condition 1:
---Select---ear thermometerhealth clinicoral thermometerbody
temperaturestaff members
Condition 2:
---Select---ear thermometerhealth clinicoral thermometerbody
temperaturestaff members
c) Input the appropriate value(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 H0Fail to
reject H0
d) Using the SPSS results,
compute the corresponding effect size(s) and indicate
magnitude(s).
If not appropriate, input and/or select "na" below.
d =_______ ; ---Select---natrivial effectsmall
effectmedium effectlarge effect
r2 =_______- ; ---Select---natrivial
effectsmall effectmedium effectlarge effect
e) Make an interpretation based on the
results.
The ear thermometer measured significantly higher temperatures than the oral thermometer.
The ear thermometer measured significantly lower temperatures than the oral thermometer.
There was no significant temperature difference between the ear and oral thermometer.
The given data is about the temperatures measured from the ear and oral from the patients by a nurse.
Hence, the data here in each category is drawn from related samples as a result, we should employ related t-test.
The given data is:
ear | oral |
97.4 | 97.8 |
97.9 | 98.6 |
96.3 | 98.9 |
97.4 | 97.6 |
98.1 | 99.1 |
97.7 | 98.2 |
We then compute the difference in the temperatures.
ear | oral | Difference (d) |
97.4 | 97.8 | 0.4 |
97.9 | 98.6 | 0.7 |
96.3 | 98.9 | 2.6 |
97.4 | 97.6 | 0.2 |
98.1 | 99.1 | 1 |
97.7 | 98.2 | 0.5 |
Next, we compute d2.
ear | oral | Difference (d) | d^2 |
97.4 | 97.8 | 0.4 | 0.16 |
97.9 | 98.6 | 0.7 | 0.49 |
96.3 | 98.9 | 2.6 | 6.76 |
97.4 | 97.6 | 0.2 | 0.04 |
98.1 | 99.1 | 1 | 1 |
97.7 | 98.2 | 0.5 | 0.25 |
Next, we compute the sums of each column. Doing so, we get:
ear | oral | Difference (d) | d^2 | |
97.4 | 97.8 | 0.4 | 0.16 | |
97.9 | 98.6 | 0.7 | 0.49 | |
96.3 | 98.9 | 2.6 | 6.76 | |
97.4 | 97.6 | 0.2 | 0.04 | |
98.1 | 99.1 | 1 | 1 | |
97.7 | 98.2 | 0.5 | 0.25 | |
SUM | 584.8 | 590.2 | 5.4 | 8.7 |
The formula for paired t-statistic is:
where n is the number of data points. Here, n = 6
Substituting the values in the formula, we get:
The degrees of freedom are df = n - 1 = 6 - 1 = 5
The level of significance given is alpha = 0.01
Using a t-table, we get a critical value of 4.032
Since, t = 2.5156<4.032, we cannot reject the null hypothesis.
Hence, we conclude that the difference is not significant.
Therefore, there was no significant difference between the temperatures measured from the ear and the oral cavity.