mary is preparing for her college entrance exams. in a practice test, she answered 12 problems in 30 minutes. at this rate, how
2 answers:
You might be interested in
Answer:
At the 0.10 level of significance the z table gives critical values of -1.645 and 1.645 for two-tailed test.
Step-by-step explanation:
We are given that the mean gross annual incomes of certified welders are normally distributed with the mean of $20,000 and a standard deviation of $2,000.
The ship building association wishes to find out whether their welders earn more or less than $20,000 annually.
<u><em>Let </em></u><u><em> = mean gross annual incomes of certified welders</em></u>
So, Null Hypothesis, :
= $20,000
Alternate hypothesis, :
$20,000
Here, null hypothesis states that the mean income of welders is equal to $20,000.
On the other hand, alternate hypothesis states that the mean income of welders is not $20,000.
Also, the test statistics that would be used here is <u>One-sample z test</u> <u>statistics</u> as we know about the population standard deviation;
T.S. = ~ N(0,1)
where, = sample mean income
= population standard deviation = $2,000
n = sample size
Now, at the 0.10 level of significance the z table gives critical values of -1.645 and 1.645 for two-tailed test.
Answer:
28
Step-by-step explanation:
Given that 12.5% of students own at least 1 pet, then the percentage of students who do not own a pet is
100% - 12.5% = 87.5%
Calculate 87.5% of 32, that is
× 32
= 0.875 × 32 = 28 ← number of students who do not own a pet
Yes, $40 is a reasonable amount to pay for the cab fare.
<em><u>Explanation</u></em>
Sheri’s cab fare was $32 and the percentage of gratuity is 20%
So, the amount of gratuity will be:
Thus, <u>the fare of the cab including the gratuity</u> will be:
As Sheri wrote a check to the cab driver for $40 , it means she paying ($40 - $38.40) or <u>$1.60 more to the cab driver</u>. So, the $40 check is a reasonable amount to pay for the cab fare.