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weqwewe [10]
3 years ago
15

In a recent study of 42 eighth graders, the mean number of hours per week that they watched television was 19.6. Assume the popu

lation standard deviation is 5.8 hours. Find the 98% confidence interval for the population mean.
a. (17.5, 21.7)
b. (14.1, 23.2)
c. (18.3, 20.9)
d. (19.1, 20.4)
Mathematics
1 answer:
olya-2409 [2.1K]3 years ago
8 0

Answer:

19.6-2.42\frac{5.8}{\sqrt{42}}=17.43    

19.6+2.42\frac{5.8}{\sqrt{42}}=21.77    

And the best option for this case would be:

a. (17.5, 21.7)

Step-by-step explanation:

Information given

\bar X= 19.6 represent the sample mean

\mu population mean

\sigma= 5.8 represent the population deviation

n=42 represent the sample size  

Confidence interval

The confidence interval for the mean is given by the following formula:

\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}   (1)

The degrees of freedom, given by:

df=n-1=42-1=41

Since the Confidence is 0.98 or 98%, the significance would be \alpha=0.02 and \alpha/2 =0.1, and the critical value would be t_{\alpha/2}=2.42

Replacing we got:

19.6-2.42\frac{5.8}{\sqrt{42}}=17.43    

19.6+2.42\frac{5.8}{\sqrt{42}}=21.77    

And the best option for this case would be:

a. (17.5, 21.7)

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ch4aika [34]

Answer:

The answer that is C

Step-by-step explanation:

The equation would be y=1/2x + 8 because the line touches the y-intercept at +8. The others would be incorrect as the line does not increase by a slop of 8/1 and/or is the y-intercept at -8.

6 0
2 years ago
2) Brian purchased pens for 75 cents each and pencils for 40 cents each he bought total of 22 writing utensils for $11.95. How m
d1i1m1o1n [39]

Answer:

13 pencils.

Step-by-step explanation:

Let x be the pens and y be the pencils

Given:

Brian purchased pens for 75 cents each and pencils for 40 cents each he bought total of 22 writing utensils for $11.95.

Total pens and pencils is 22

So, x+y=22----------------(1)

And he bought all utensils for $11.95. and each pen for 75 cents and pencils for 40 cents.

0.75x+0.40y=11.95------------(2)

solve equation 1 and equation 2 for x and y.

From equation 1.

x+y=22

y=22-x----------------(3)

put y value in equation 2.

0.75x+0.4(22-x)=11.95

0.75x+0.4\times 22-0.4x=11.95

0.75x+8.8-0.4x=11.95

0.75x-0.4x=11.95-8.8

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x=\frac{3.15}{0.35}

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Now substitute x value in equation 3.

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So, he buy 13 pencils.

5 0
3 years ago
What is 15% of 10.00
natka813 [3]

$1.50

I hope this is what you need

3 0
3 years ago
Image is down below :)
zhuklara [117]
-3, 1 is the answer because the spot is on the -3 and in the first low with the Y-axis and stuff .
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8 0
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