Which expressions are correct for the situation?
2 answers:
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Answer:
The 95% confidence interval for the mean change in blood pressure, , is 1.744 <
< 2.816
Step-by-step explanation:
The parameters given are;
The number of people in the sample, n = 9
The average drop in blood pressure, = 2.28 points
The standard deviation, σ = 0.82
The confidence level = 95%
The formula for confidence interval with a known mean is given as follows;
Where:
= z - score at 95% confidence level = 1.96
We therefore have;
Which gives the 95% confidence interval for the mean change in pressure, , is given as follows;
1.744 < < 2.816
Answer:
Claim is false
Step-by-step explanation:
Claim : A credit reporting agency claims that the mean credit card debt in a town is greater than $3500.
n = 20
Since n <30
So we will use t test
Formula :
s = standard deviation = 391
x = 3600
n = 20
Degree of freedom = n-1 = 20-1 = 19
α=0.10
So, using t table
= 1.72
t critical > t calculated
So we accept the null hypothesis
Hence we reject the claim that the mean credit card debt in a town is greater than $3500.