Sarah is researching the connection between the time students spend watching television and their performance in school. Her stu
2 answers:
Answer: D) 52.5
Step-by-step explanation:
The equation for inverse variation between two quantities x and y is given by :-
, where k is the constant of variation, for this relationship. (1)
Given : Sarah studies indicate that there is an inverse relationship between TV time and GPA, and that a student who watched 15 hours of TV per week can be expected to have a GPA of 3.5.
Then from (1) the constant of variation is given by :-
Hence, the required answer is option D) 52.5 .
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The hypothesis test shows that we reject the null hypothesis and there is sufficient evidence to support the claim that the return rate is less than 20%
<h3>What is the claim that the return rate is less than 20% by using a statistical hypothesis method?</h3>The claim that the return rate is less than 20% is p < 0.2. From the given information, we can compute our null hypothesis and alternative hypothesis as:
Given that:
Sample size (n) = 6965
Sample proportion
The test statistics for this data can be computed as:
z = -2.73
From the hypothesis testing, since the p < alternative hypothesis, then our test is a left-tailed test(one-tailed.
Hence, the p-value for the test statistics can be computed as:
P-value = P(Z ≤ z)
P-value = P(Z ≤ - 2.73)
By using the Excel function =NORMDIST (-2.73)
P-value = 0.00317
P-value ≅ 0.003
Therefore, we can conclude that since P-value is less than the significance level at ∝ = 0.01, we reject the null hypothesis and there is sufficient evidence to support the claim that the return rate is less than 20%
Learn more about hypothesis testing here:
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Answer:
Yes, there is a difference between the population mean for the math scores and the population mean for the writing scores.
Test Statistics = follows
.
Step-by-step explanation:
We are provided with the sample data showing the math and writing scores for a sample of twelve students who took the SAT ;
Let A = Math Scores ,B = Writing Scores and D = difference between both
So, = Population mean for the math scores
= Population mean for the writing scores
Let = Difference between the population mean for the math scores and the population mean for the writing scores.
<em> Null Hypothesis, </em><em> : </em>
<em> or </em>
<em> = 0 </em>
<em> Alternate Hypothesis, </em><em> : </em>
<em> or </em>
<em> 0</em>
Hence, Test Statistics used here will be;
follows
where, Dbar = Bbar - Abar
=
n = 12
Student Math scores (A) Writing scores (B) D = B - A
1 540 474 -66
2 432 380 -52
3 528 463 -65
4 574 612 38
5 448 420 -28
6 502 526 24
7 480 430 -50
8 499 459 -40
9 610 615 5
10 572 541 -31
11 390 335 -55
12 593 613 20
Now Dbar = Bbar - Abar = 489 - 514 = -25
Bbar = =
= 489
Abar = =
= 514
∑ = 22600 and
=
=
= 37.05
So, Test statistics = follows
= follows
= -2.34
<em>Now at 5% level of significance our t table is giving critical values of -2.201 and 2.201 for two tail test. Since our test statistics doesn't fall between these two values as it is less than -2.201 so we have sufficient evidence to reject null hypothesis as our test statistics fall in the rejection region .</em>
Therefore, we conclude that there is a difference between the population mean for the math scores and the population mean for the writing scores.