Answer:
A sample of 17 must be selected.
Step-by-step explanation:
We have that to find our
level, that is the subtraction of 1 by the confidence interval divided by 2. So:

Now, we have to find z in the Z-table as such z has a p-value of
.
That is z with a pvalue of
, so Z = 2.054.
Now, find the margin of error M as such

In which
is the standard deviation of the population and n is the size of the sample.
The standard deviation from a previous study is 4 hours.
This means that 
How large a sample must be selected if he wants to be 96% confident of finding whether the true mean differs from the sample mean by 2 hours?
A sample of n is required.
n is found for M = 2. So



Simplifying both sides by 2:



Rounding up:
A sample of 17 must be selected.
Answer:
The number of ways is 13860 ways
Step-by-step explanation:
Given
Senior Members = 10
Junior Members = 12
Required
Number of ways of selecting 6 students students
The question lay emphasis on the keyword selection; this implies combination
From the question, we understand that
<em>4 students are to be selected from senior members while 2 from junior members;</em>
The number of ways is calculated as thus;
<em>Ways = Ways of Selecting Senior Members * Ways of Selecting Junior Members</em>
<em />







<em>Hence, the number of ways is 13860 ways</em>
Answer:
a. Yes
See explanation below.
Step-by-step explanation:
Assuming that if the question is if we can use the normal approximation for the true proportion.
For this case we have n = 40 and p = 0.3 (probability of success)
We need to check some conditions:
1) Random sample : This condition is satisfied since the problem says that she randomly select 40 records
2) 

3) 10% condition: the random sample is assumed to be less than 10% of the original population size (assumed)
The population proportion have the following distribution
So then as we can see the normal approximation for this case makes sense since we have all the 3 conditions satisfied so then the answer would be:
a. Yes
If n is ten then the expression would change to
2(10)+4
20+4
so your answer would be 24
Answer:
11
Step-by-step explanation:
if george is 30 than edward would be 15 as he is twice younger than george
and robert would be 11 as he is 4 year younger than edward.