Mrs. Myles gave the same test to both her first and third period class. In first period, the mean was 75 and the range was 30. I
2 answers:
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The number of songs that Deante' would have downloaded during month 9 is 58 songs.
<h3>What is a regression line?</h3>A regression line is a statistical line that best describes the behavior of a data set and such, it is a line that best fits a set of data.
By using Microsoft excel to plot the data on a scatter plot, we can logically deduce that line of best fit for the songs downloaded is given by:
y = 2.03x + 39.7
Thus, the number of songs that Deante' would have downloaded during month 9 is:
y = 2.03(9) + 39.7
y = 18.27 + 39.7
y = 57.97 ≈ 58 songs.
Read more on regression here: brainly.com/question/26059078
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Answer:
(2)
The critical value for 95% of confidence interval now can be founded using the normal distribution. And in excel we can use this formla to find it:"=-NORM.INV(0.025,0,1)", and we got , replacing into formula (2) we got:
So the answer for this case would be n=25 rounded up to the nearest integer
Step-by-step explanation:
Previous concepts
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
represent the sample mean for the sample
population mean (variable of interest)
represent the population standard deviation
n represent the sample size (variable of interest)
Solution to the problem
The confidence interval for the mean is given by the following formula:
The margin of error is given by this formula:
(1)
And on this case we have that ME =0.1 and we are interested in order to find the value of n, if we solve n from equation (1) we got:
(2)
The critical value for 95% of confidence interval now can be founded using the normal distribution. And in excel we can use this formla to find it:"=-NORM.INV(0.025,0,1)", and we got , replacing into formula (2) we got:
So the answer for this case would be n=25 rounded up to the nearest integer