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SVEN [57.7K]
3 years ago
6

Leo wants to determine the average number of texts middle school students send in a day. Since all middle school students are en

rolled in history, he randomly surveyed 4 students from each of Mr. Barnes’s eighth-grade history classes. Ms. Lopez and Mrs. Frank also teach eighth-grade history. What should Leo do to ensure his sample is representative of all middle school students?
He should take the sample as is because he randomly surveyed students in each of Mr. Barnes’s classes.
He should also take a sample from Ms. Lopez’s and Mrs. Frank’s classes so that each student has the same chance of being chosen.
He should also take a sample from each of the other history classes in all of the other grades in the middle school.
He should survey all the students in all the history classes to make sure he collects enough data.
Mathematics
2 answers:
Svet_ta [14]3 years ago
7 0

Answer:

The answer is D!!!!!!!!!

rewona [7]3 years ago
3 0

Answer:

D is the correct answer. Have a great day!!! :)

You might be interested in
What is the greatest common factor of the polynomial 40x^7+135x^4+5x^4
tensa zangetsu [6.8K]

5x^4

Step-by-step explanation:

simply we take 5x^4 bec. it can be divided by 40 and 135

7 0
2 years ago
in a program designed to help patients stop smoking 232 patients were given sustained care and 84.9% of them were no longer smok
grandymaker [24]

Answer:

z=\frac{0.849 -0.8}{\sqrt{\frac{0.8(1-0.8)}{232}}}=1.869  

p_v =2*P(Z>1.869)=0.0616  

If we compare the p value obtained and the significance level given \alpha=0.05 we see that p_v>\alpha so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can said that at 5% of significance the proportion of adults were no longer smoking after one month is not significantly different from 0.8 or 80% .  

Step-by-step explanation:

1) Data given and notation

n=232 represent the random sample taken

X represent the adults were no longer smoking after one month

\hat p=0.849 estimated proportion of adults were no longer smoking after one month

p_o=0.80 is the value that we want to test

\alpha=0.05 represent the significance level

Confidence=95% or 0.95

z would represent the statistic (variable of interest)

p_v represent the p value (variable of interest)  

2) Concepts and formulas to use  

We need to conduct a hypothesis in order to test the claim that the true proportion is 0.8.:  

Null hypothesis:p=0.8  

Alternative hypothesis:p \neq 0.8  

When we conduct a proportion test we need to use the z statistic, and the is given by:  

z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}} (1)  

The One-Sample Proportion Test is used to assess whether a population proportion \hat p is significantly different from a hypothesized value p_o.

3) Calculate the statistic  

Since we have all the info requires we can replace in formula (1) like this:  

z=\frac{0.849 -0.8}{\sqrt{\frac{0.8(1-0.8)}{232}}}=1.869  

4) Statistical decision  

It's important to refresh the p value method or p value approach . "This method is about determining "likely" or "unlikely" by determining the probability assuming the null hypothesis were true of observing a more extreme test statistic in the direction of the alternative hypothesis than the one observed". Or in other words is just a method to have an statistical decision to fail to reject or reject the null hypothesis.  

The significance level provided \alpha=0.05. The next step would be calculate the p value for this test.  

Since is a bilateral test the p value would be:  

p_v =2*P(Z>1.869)=0.0616  

If we compare the p value obtained and the significance level given \alpha=0.05 we see that p_v>\alpha so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can said that at 5% of significance the proportion of adults were no longer smoking after one month is not significantly different from 0.8 or 80% .  

6 0
3 years ago
A printer is printing photos. For every 6 photos, the printer takes 3 minutes.
ki77a [65]

Answer:

Number of Photos - 6, 8, 12, 14, 18

Time (Minutes) - 3, 4, 6, 8, 9

hope this helps.

4 0
2 years ago
Slope of 2 and passes through the point (-4,3). Write the equation in slope intercept form
erastova [34]

Answer:

The equation is y = 2x + 11.

Step-by-step explanation:

It is given that the gradient of the equation is 2. Using slope-form formula, y = mx+b where m is gradient and b is y-intercept. In order to find b, you have to substitute x-coordinate and y-coordinate into the equation :

y = mx + b

m = 2

At(-4,3),

3 = 2(-4) + b

b = 3 - 2(-4)

= 11

8 0
2 years ago
There are 5 numbers, they are- 5,8,2,9,10
Crank

Answer:

Mean: 6.8

Median: 2

Mode: There is no mode of the data set

Step-by-step explanation:

Finding the mean: 5+8+2+9+10= 34 divided by the numbers of the data set which is 5= 6.8

Finding the median: The middle of the data set which is 2

Finding the mode: the most frequently occurring number which doesn't appear in this data set which means there is none.

8 0
2 years ago
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