A football coach gives half his players a protein bar to eat before each game; the other players do not receive the protein bar.
1 answer:
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Answer:
The sample consisting of 64 data values would give a greater precision.
Step-by-step explanation:
The width of a (1 - <em>α</em>)% confidence interval for population mean μ is:
So, from the formula of the width of the interval it is clear that the width is inversely proportion to the sample size (<em>n</em>).
That is, as the sample size increases the interval width would decrease and as the sample size decreases the interval width would increase.
Here it is provided that two different samples will be taken from the same population of test scores and a 95% confidence interval will be constructed for each sample to estimate the population mean.
The two sample sizes are:
<em>n</em>₁ = 25
<em>n</em>₂ = 64
The 95% confidence interval constructed using the sample of 64 values will have a smaller width than the the one constructed using the sample of 25 values.
Width for n = 25:
Width for n = 64:
Thus, the sample consisting of 64 data values would give a greater precision
Answer:
There is no significant difference between the means.
Step-by-step explanation:
Given is the data set for X1 and x2 are we have to do a paired t test.
(Two tailed test at 5% significance level)
Mean difference = 1.00
Std error for difference = 1.225
df=4
Test statistic = mean diff/se = 1.826
p value =0.142
Since p >0.05 our alpha we accept H0
There is no significant difference before and after averages at 5% sign. level.