Question to try for December 7:
Henry Cavendish was a scientist who was trying to figure out the average density of the Earth using a torsion balance (he was doing this in 1798).
He reproduced the experiment 29 times (the results are below in the .csv file). given to you was the sd of 0.25
QUESTION: Based on his measurement, give a 95% Confidence Interval for the average density of the earth. Be sure to walk through the steps, check your data, etc. etc.
Start in the book:
6.22, 6.25, 6.28, 6.33
Mundt Question One:
Here are the IQ scores of 31 seventh-graders in a midwest school district:
seventhgrade<-c(114, 108, 111, 100, 130, 103, 104, 120, 74, 89, 132, 112, 102, 111, 107, 91, 128, 103, 114, 118, 98, 114, 119, 96, 103, 86, 112, 105, 72, 112, 93)
We know the population standard deviation on IQ tests is 15.
a) We expect IQ scores to be approximately normal, so before we run more tests, check to make sure this data has no major outliers. Be sure to exaplin what steps you take. If you feel the need to remove a data point, call me over and let's chat.
b) Now find, with 99% accuracy, what we believe the population mean on the IQ test to be.
Mundt Question Two:
I have given you a sheet with three sets of data on it (they are described in the paragraph above them).
1) Check that each set of data has no influential points that need removed (check each set separately). Show the steps you take to prove there are no outliers. If there are points, you believe that need removed, call me over and let's chat.
2) Assume the amount spent on dinner has a population standard deviation of 2.5 . Based upon that, find a 95% confidence interval for the true mean for each of the three data sets.
3) In a brief paragraph, draw any conclusions that we might be able to make about the data. Specifically--can we conclude anything about whether or not smells cause people to spend more?
FOR CLASS: 12/5
Here is the set of # doctors per 100,000 people per state (on sheet):
doctors<-c(213, 222, 208, 203, 259, 258, 363, 248, 245, 220, 310, 169, 272, 213, 187, 220, 230, 264, 267, 411, 450, 240, 281, 181, 239, 221, 239, 186, 260, 306, 240, 389, 253, 242, 261, 171, 263, 294, 351, 230, 219, 261, 212, 209, 362, 270, 265, 229, 254, 188, 798)
the population standard deviation (in this case from the states) is 98.
QUESTION: in the united states, we could be 95% confident of how many doctors per 100,000 people?
Studying
Students were asked how many minutes they studied per week night. The results are below. The population standard deviation was: 70
men<-c(90, 90, 150, 240, 30, 0, 120, 45, 120, 60, 230, 200, 30, 30, 60, 120, 120, 120, 90, 120, 240, 60, 95, 120, 200, 75, 300, 30, 150, 180)
women<-c(180, 120, 150, 200, 120, 90, 120, 180, 120, 150, 60, 240, 180, 120, 180, 180, 120, 180, 360, 240, 180, 150, 180, 115, 240, 170, 150, 180, 180, 120)
QUESTION: What statements can we make about the study habits of women as compared to men?