Note :- If sample size n > 30 OR Population standard deviation σ is given then We use Z test.
If sample size n < 30 AND Population standard deviation σ is unknown then we use t test.
In this question we are not given Population standard deviations σ1 and σ2.
Also n1 = 14 and n2 = 13 both sample sizes are LESS than 30.
Therefore we use t test.
Given :- Assume the population standard deviations are equal. ( σ1 = σ2)
then Degrees of freedom = n1 + n2 - 2 = 14 + 13 - 2 = 25.
(kindly find the image attached with this solution)
Answer :- Therefore 25 degrees of freedom are used to find the t critical value.
A) 1 out of 4
B) 1 out of 4
Answer: I'm pretty sure its -0.74
Answer:
4m
Step-by-step explanation:
m+m+m+m
There is an implied 1 in front of each term
1m+1m+1m+1m
Factor out the m
(1+1+1+1)m
4m
Answer:
The 99% confidence interval is 
Step-by-step explanation:
From the question we are told that
The sample size is n = 100
The sample mean is 
The population standard deviation is 
From the question we are told the confidence level is 99% , hence the level of significance is
=> 
Generally from the normal distribution table the critical value of 
is
Generally the margin of error is mathematically represented as
=> 
Generally 95% confidence interval is mathematically represented as
=> 
=> 
