Recent recommendations from a medical association stated 60 minutes of Physical

Question

Recent recommendations from a medical association stated 60 minutes of Physical Activity per day is healthy. A survey of cardiovascular risk factors with a random sample of 50 adults found mean of 38 minutes and standard deviation of 19 minutes. A one sample t-test of difference (38-60) yielded a p<.001. The researcher decided that sampling error could account for the statistically significant difference between their sample mean so they decided to redo the survey with a different but larger sample of 200 adults. Lets say they found a similar sample mean (38 minutes) and Standard Deviation (19 minutes). Based on new sample data. will they now conclude that Physical activity levels are 60 minutes a day? (Yes or no) and why

Explanation / Answer

for hypothesis test,

h0:mu=60

Ha:mu<60

for n=50

Z = (38 - 60)/(19/sqrt(50)) = -8.188

The two-tailed p-value is less than 0.0001.

Since p <<< alpha(0.05), null hhypothesis can be rejected to say that the physical activity is less than recommended.

for n=200

t value =-16.37

p value = 0.00001

The result is significant at p < .001

reject null hypothesis

accept Ha:mu<60

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