Question

A researcher at UniSA’s School of Health Sciences believes that energy drink consumption may increase heart rate. She believes that heart rate in beats per minute (bpm) is normally distributed with an average of 70 bpm for adults. To test her belief, she takes a random sample of 25 adults who regularly consume energy drink. Their heart rates are 65, 64, 75, 79, 60, 84, 63, 91, 81, 98, 92, 69, 78, 85, 88, 87, 70, 80, 73, 74, 83, 79, 77, 71 and 90.

1. Set up the null and alternative hypotheses (use appropriate statistical signs and procedures).
2. Can the researcher conclude at the 5% significance level that energy drink consumption increases heart rate? (Please copy the hypothesis test results from Excel and paste them onto the space provided below).
3. Under what circumstances the researcher will commit a Type I error and a Type II error?

Answer 1

  

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b)

t-Test:
	Variable 1
Mean	78.24
Variance	98.85667
Observations	25
Hypothesized Mean Difference	70
df	24
t Stat	4.143757
P(T<=t) one-tail	0.000183
t Critical one-tail	1.710882
P(T<=t) two-tail	0.000366
t Critical two-tail	2.063899

Yes, Researcher can conclude that the energy drink consumption increases heart rate. ( P-value is less than 0.05)

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c) (i) If Rejecting Ho when Ho is true results Type I error.

fail to reject Ho when Ho is false results Type II error

Type I error = Actually energy drink do not increase the heart rate but we are assuming they are increasing due to lack of evidence.

Type II error = The energy drink consumption increases heart rate but evidence donot supporting it