What is 25 * 6 * 2/5.
1 answer:
You might be interested in
Answer:
a)
b) n = 381
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of , and a confidence level of
, we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of .
The margin of error is:
90% confidence level
So , z is the value of Z that has a pvalue of
, so
.
a. Assume that nothing is known about the percentage of computers with new operating systems. n = ?
When we do not know the proportion, we use , which is when we are going to need the largest sample size.
The sample size is n when M = 0.01.
b. Assume that a recent survey suggests that 99% of computers use a new operating system. n = ?
Now we have that . So
Rouding up
n = 381
Answer:
H0: μ ≤ 34
H1: μ > 34
The z-test statistic is ≈ 1.8
The critical z-score is 1.28
we fail to reject the null hypothesis H0: μ ≤ 34
Step-by-step explanation:
H0: μ ≤ 34
H1: μ > 34
The z-test statistic is calculated using the formula:
z= where
- X is the average class size found in the sample (35.6)
- M is the mean according to the null hypothesis (34)
- s is the standard deviation for class size (9)
then z= ≈ 0.18
The critical z-score is 1.28 for α=0.10 (one tailed)
Because the test statistic is less than the critical value, do not reject the null hypothesis.