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yulyashka [42]
3 years ago
13

A researcher randomly surveyed two separate age groups to determine the number of hours teens spend on the Internet each week. T

he results are shown in this table. 13- to 14-year-olds 12 8 7 8 9 6 7 7 9 10 15- to 16-year-olds 15 6 21 12 13 12 8 9 7 10 Based on these results, which conclusions can you draw about these two groups of teens? Select each correct answer.
A. On average, 15- to 16-year-olds spend a few hours more on the Internet each week compared to 13- to 14-year-olds.
B. On average, 15- to 16-year-olds spend a few hours less on the Internet each week compared to 13- to 14-year-olds.
C. On average, the two groups of teens spend about the same amount of time each week on the Internet.
D. The amount of time that 15- to 16-year-olds spend on the Internet each week is more variable than the amount time 13- to 14-year-olds spend.
E. The amount of time 15- to 16-year-olds spend on the Internet each week is less variable than the amount time 13- to 14-year-olds spend.
F. The amount of time that the two groups spend on the Internet each week varies by about the same amount.
Mathematics
2 answers:
Papessa [141]3 years ago
8 0
The answer to this is A.
MrRissso [65]3 years ago
3 0

Answer:

Option A and D.

Step-by-step explanation:

In this question the given table is of two separate age groups to determine the number of hours teens spent on the internet each week.

From the table

average hours spent by teens between the age of 13-14 years old

=  (12+8+7+8+9+6+7+7+9+10+15)/10 = 83/10 = 8.3 hours

average hours spent by teens between age of 15-16 years old

=(15+6+21+12+13+12+8+9+7+10)/10 = 113/10 = 11.3 hours

From these averages we can conclude

A) 15-16 year old spend a few hours more than 13-14 year old teens.

D. The amount that 15-16 year old teens spend on internet is more variable than the time spent by 13-14 years old.

Option A and D are the correct options.

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9. When the sun makes an angle of o above the horizon, a building casts a shadow 17 feet long
Mkey [24]

Answer:

A. tan 38° = opposite/adjacent

opposite = (tan 38°)(adjacent)

opposite = (0.31)(17 ft)

opposite = 5.27 ft

B. height is = 5.27 ft

4 0
3 years ago
In a study of 420,095 Danish cell phone users, 135 subjects developed cancer of the brain or nervous system (based on data from
Maksim231197 [3]

Answer:

z=\frac{0.0003214 -0.00034}{\sqrt{\frac{0.00034(1-0.00034)}{420095}}}=-0.654  

p_v =2*P(Z  

So the p value obtained was a very high value and using the significance level given \alpha=0.005 we have p_v>\alpha so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can say that the true proportion not differs significantly from the specified value of 0.00034 or 0.034%.

Step-by-step explanation:

1) Data given and notation  

n=420095 represent the random sample taken

X=135 represent the subjects developed cancer of the brain or nervous system (based on data from the Journal of the National Cancer Institute as reported in USA Today)

\hat p=\frac{135}{420095}=0.0003214 estimated proportion of subjects developed cancer of the brain or nervous system (based on data from the Journal of the National Cancer Institute as reported in USA Today)

p_o=0.00034 is the value that we want to test

\alpha=0.005 represent the significance level

Confidence=99.5% or 0.995

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 brain or nervous system at a rate that is different from the rate of 0.0340% :  

Null hypothesis:p=0.00034  

Alternative hypothesis:p \neq 0.00034  

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{0.0003214 -0.00034}{\sqrt{\frac{0.00034(1-0.00034)}{420095}}}=-0.654  

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=0.005. 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  

So the p value obtained was a very high value and using the significance level given \alpha=0.005 we have p_v>\alpha so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can say that the true proportion not differs significantly from the specified value of 0.00034 or 0.034%.  

4 0
3 years ago
PLEASE HELP FAST!!!
Llana [10]

Answer:

4500 miles

Step-by-step explanation:

750 rounded to the nearest hundred is 800. 2,488 rounded to the nearest hundred is 2,500. 155 rounded to the nearest hundred is 200. 1,015 rounded to the nearest hundred is 1,000. So 800+2,500+200+1,000= 4,500

8 0
3 years ago
I’ll give brainlest to the first one who answer the one my mouse is on it’s not that one!
Natalija [7]

Answer:

The answer is A

Step-by-step explanation:

4 0
3 years ago
Square has a side length of (x-5). If the perimeter is 24, what is the<br> value of x? *
san4es73 [151]

Answer:

11 units

Step-by-step explanation:

<em>hey there,</em>

<em />

< A square has 4 sides that are all always equal to each other. The perimeter is all the sides summed up together. That means (for example), if one side of the square is 2 cm, then we know that the perimeter is 8 cm, because 2 + 2 + 2 + 2 = 8 (or 2×4=8).

Here we are given that one side is equal to "x-5". Pretend that is a number and solve as I did just right above:

(x-5)×4 = 4x -20

Now we know that the perimeter is (4x-20) units (when you don't know what the units are then just put "units").

We also know that the perimeter can be a number which is 24. That means these two values are equal to each other.

4x-20 = 24

Now solve! Bring x to one side, and all the numbers to the other side.

4x = 44

x = 11

We now know that the value of one side of the square (x) is equal to 11 units. >

<u>Hope this helped! Feel free to ask anything else.</u>

6 0
3 years ago
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