. A study of one thousand teens found that the number of hours they spend on social networking sites each week is normally distr
2 answers:
We are given the following data:
Sample Size = n = 1000
Sample Mean = u = 15 hours
Population Standard Deviation = s = 2 hours
Since we know the population standard deviation, we can use z distribution to find the confidence interval about the mean. z value for 95% confidence interval is 1.96.
Formula for the confidence interval is:
Using the values in the formula, we get:
Therefore, the 95% confidence interval about the population mean is 14.88 hours to 15.12 hours. So B option is the correct answer.
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Given:
Annual interest rate = r%
Growth factor : x = 1 + r
The below function gives the amount in the account after 4 years when the growth factor is x .
To find:
The total amount in the account if the interest rate for the account is 3% each year and initial amount.
Solution:
Rate of interest = 3% = 0.03
Growth factor : x = 1 + 0.03 = 1.03
We have,
Substitute x=1.03 in the given function, to find the total amount in the account if the interest rate for the account is 3% each year.
Therefore, the total amount in the account is 2431.31 if the interest rate for the account is 3% each year.
For initial amount the rate of interest is 0.
Growth factor : x = 1 + 0 = 1
Substitute x=0 in the given function to find the initial amount.
Therefore, 2250 was put into the account at the beginning.
Use these equations when converting polar equations to parametric equations:
We know that , so substitute that into both equations for x and y.
Now, replace with any variable that you want to represent the parametric equations in. I'll use the standard variable,
Thus, represented in parametric form is:
Let me know if you need any clarifications, thanks!
~ Padoru