a survey, 16 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $46 and standard deviation of $8. Find the margin of error at a 95% confidence level. Give your answer to two decimal places.

A survey was conducted that asked 972 people how many books they had read in the past year. Results indicated that x=14.1 books and s=16.6 books. Construct a 95​% confidence interval for the mean number of books people read. Interpret the interval. Construct a 95​% confidence interval for the mean number of books people read and interpret the result. Select the correct choice below and fill in the answer boxes to complete your choice. ​(Use ascending order. Round to two decimal places as​ needed.)     A. If repeated samples are​ taken, 95​%   {    } of them will have a sample mean between nothing and nothing.   B. There is a 95​% probability that the true mean number of books read is between {      }nothing and {      }nothing.   C. There is 95​% confidence that the population mean number of books read is between {      }nothing and {      }nothing.

The average person uses 130 gallons of water daily. If the standard deviation is 35 gallons , find the probability that the mean of a randomly selected sample of 25 people will be between 110 and 135 gallons.Assume the variable is normally distrubuted

On a verbal skill test, the mean was 72 and the standard deviation was 7. If John scored 75, what was his z-score?

A population has a Mean of 100 and a standard deviation of 15.  A sample of 20 college students is measured and the Sample mean is 125.  What is the standard error?  Show the math.

mt-nut Degrees of Freedom 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 N823 & 89882888 22 24 25 26 27 29 30 40 50 60 70 80 90 100 0.996 - 0.010 0.072 0207 0.412 0.676 0.999 1.344 1.735 2.156 2.603 3.074 3.565 4.075 4.601 5.142 5.697 6.265 6.844 7.434 8.034 8.643 9.260 9.856 10.520 11.160 11.508 12.461 13.121 13.787 20.707 27.991 35.534 43.275 51.172 59.196 67.328 0.996 0.99 - 0.020 0.115 0.297 0.554 0.872 1.239 1.646 2.068 2.558 3.053 3.571 4.107 4.660 5.229 5.812 6.406 7.015 7.633 8.260 8.897 9.542 10.196 10.856 11.524 12.196 12.879 13.565 14.257 14.964 22.164 29.707 37.485 45.442 53.540 61.754 70.065 0.99 0.975 0.001 0.051 0216 0.484 0.831 1.237 1.690 2.180 2.700 3247 3.816 4.404 5.009 5.629 6.262 6.908 7.564 8.231 8.907 9.591 10.283 10.982 11.689 12.401 13.120 13.844 14.573 15.308 16.047 16.791 24.433 32.357 40.482 48.758 57.153 65.647 74 222 0.975 0.95 0.004 0.103 0.352 0.711 1.145 1.635 2.167 2.733 3.325 3.940 4.575 5.226 5.892 6.571 7.261 7.962 8.672 9.390 10.117 10.851…

The prices of all college textbooks follow a bell-shaped distribution with a mean of $108 and a standard deviation of $21. What percentage of the price that is more than 140? Show your works and read the table.

According to the U.S. Census, the average adult woman is the United States is 65 inches tall and the standard deviation is 3 inches.  If Zsike is 67 inches tall, what is her z-score?

Carla scored a 31 on her ACT and an 750 on her SAT.  If the mean and standard deviation for the ACT are 18 and 7, respectively; and the mean and standard deviation of the SAT are 500 and 150, respectively - what is her percentile rank on each exam? Percentile rank of ACT  Percentile rank of SAT  On which exam did she do better?

Mario's weekly poker winnings have a mean of $353 and a standard deviation of $67. Last week he won $185. How many standard deviations from the mean is that?