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Taya2010 [7]
3 years ago
5

Suppose that, in 1995, the weight of 16-year old males in the United States was normally distributed with a mean of 143 lbs and

standard deviation equal to 15 lbs. Suppose that Roger, a public health researcher, believes that the popularity of video and computer gaming has made teenagers less active, and predicts that 16-year old males today weigh more than 16-year old males did in 1995. To test the theory, he chooses a random sample of 50 16-year old males and records their weights. The average weight of the sample is 147 lbs. Roger uses a z ‑ test to test the hypothesis that the average weight of 16-year old males has increased. He calculates the z ‑ statistic as 1.89 standard deviations above the mean. Use this standard normal z-distribution table to calculate the p-value of this statistic. Give your answer as a decimal rounded to four places. Also how to determin if this is a one-sided or two-sided test?
Mathematics
1 answer:
seropon [69]3 years ago
4 0

Answer:

Step-by-step explanation:

The null hypothesis is:

H0: μ(1995)=μ(2019)

The alternative hypothesis is:

H1: μ(1995)<μ(2019)

Because Roger wants to know if mean weight of 16-old males in 2019 is more than the mean weight of 16-old males in 1995 the test only uses one tail of the z-distribution.  It is not a  two-sided test because in that case the alternative hypothesis would be:  μ(1995)≠μ(2019).

To know the p-value, we use the z-statistic, in this case 1.89 and the significance level. Because the problem does not specify it, we will search for the p-value at a 5% significance level and at a 1%.

For a z of 1.89 and 5% significance level, the p-value is: 0.9744

For a z of 1.89 and 1% significance level, the p-value is: 0.9719

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Question 1b.
Ainat [17]

Answer:  i) Reasonably symmetric

=============================================================

Explanation:

The data set is

35,40,45,49,51,54,57,58,58,64,68,68,75,77

Erase the outer pair of values (35 and 77) to end up with this smaller set

40,45,49,51,54,57,58,58,64,68,68,75

Repeat and erase off the outer values (40 and 75) to end up with

45,49,51,54,57,58,58,64,68,68

Keep going until we have either one or two elements left

  • 49,51,54,57,58,58,64,68
  • 51,54,57,58,58,64
  • 54,57,58,58
  • 57,58

At this point, we see that the center is between these two last values. So the median is (57+58)/2 = 57.5

--------------------------------

The center is at 57.5

Let L = {35,40,45,49,51,54,57} consist of the set of numbers lower than the median

Let U = {58,58,64,68,68,75,77} be the upper set of values larger than the median.

The middle of set L is 49 and the middle of set U is 68. So Q1 and Q3 are 49 and 68 respectively.

From that, we see the IQR = Q3 - Q1 = 68-49 = 19

Let A and B be the lower and upper fence

We would then say

A = Q1 - 1.5*IQR = 49-1.5*19 = 20.5

B = Q3 + 1.5*IQR = 68 + 1.5*19 = 96.5

Notice how all of the given data values are between A = 20.5 and B = 96.5, which means we don't have any outliers.

Furthermore, if we plotted a box-and-whisker plot (see below), we can see that the two whiskers are fairly the same length. It's not perfect but they're reasonably symmetric. Similarly, the median is somewhat in the middle of the box itself. So this gives a rough idea that the data set we're dealing with is fairly symmetric.

More confirmation can be in the form of a histogram which is also part of the image below. This histogram is fairly symmetric as the left half is nearly (not perfectly) a mirror image of the right half, and vice versa. No one side pulls too far out to create a highly skewed distribution.

8 0
3 years ago
A t-shirt increased in price by 1/7. After the increase it was priced at £56. What was the original price of the t-shirt?
Dominik [7]

Answer:

£48

Step-by-step explanation:

56 ÷ 7 = £8

56 - 8 = £48

Please let me know if my answer is correct.

3 0
2 years ago
Read 2 more answers
A sample of n = 9 scores is obtained from a population with m = 70 and s = 18. if the sample mean is m = 76, then what is the z-
mr Goodwill [35]
N times m equals the correcr answrr

8 0
3 years ago
if there both consecutive doesn't that mean that there both -9 so how is one bigger an one smaller.... ​
MrRissso [65]

Answer:

-14

Step-by-step explanation:

have a great day good luck

5 0
3 years ago
Roundup Racquets restrings tennis racquets for $22. If the store restrings 20 racquets each month, what is the monthly revenue f
ser-zykov [4K]

Answer:

The revenue would be $ 440

Step-by-step explanation:

Consider the correct complete question is,

"Roundup Rackets restrings a tennis racket for $22. If the store restrings 20 rackets each month, what is the monthly revenue from restringing rackets."

Thus,

The price for restrings each tennis racket = $ 22,

Number of rackets re stringed in a month = 20,

Hence, the monthly revenue = price of restrings each tennis racket × number of rackets re stringed

= 22 × 20

= $ 440

7 0
3 years ago
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