Classify each of the following variables which
were recorded on a sample of students.
a. course in which enrolled
A small city Universitys records indicated that,
historically, half its students lived in the city, a third
lived in th
Predict, if possible, the expected number of
holidays booked by a travel agent who has been
employed for 20 months.
Exercise 2: For the scatter plots below circle the
best estimate of the coefficient of determination.
Note: OK to predict holida
We first need to decide which is the dependent
and which is the independent variable. Here
we would like to predict number of holidays
from time so:
Data were recorded for a sample of 195 British
males. Their current age and age at la
Could the mean number of times that children wash
dishes per month be the same for the three families?
For the analysis we need only the Between and Within
Between Group (SSG) = ni(yi y)
2+3(4 4.44)2+4(6 4.44)2 = 22.22
= 2(2 4.44)
First we need to look at the design of the problem
to see if it is paired or not.
Look at the following problems and determine
whether the experiments are paired or independent.
To evaluate the effectiveness o
Exercise 1: Calculate a 95% confidence interval
to estimate the mean completion time for 2011
forms and confirm that 80 minutes is a reasonable
value for the population mean.
Standard bottles of wine are labelled as containing
750 ml, on averag
How good is our point estimate, y?
Sample Means and Standard Errors
This depends on the standard error.
Well start by looking at the case where the
population standard, , is known:
Suppose ages of all female cardiac patients have
= 18. Co
Comment on the distribution of sample means
from samples of size two:
Histogram of consultation times
Let A = Anna fails an exam
Obtain P(Y = biology) and determine whether
being male and majoring in biology are
Let B = Bryn fails the exam
If P(A) = 0.5, P(B) = 0.2 and P(A B) = 0.1
P(Y = biology) = 10/200 + 40/200
Solution to Exercise 1
Lucy works for a mobile phone company selling
contracts to customers who visit the store. She
records the number of contracts sold each day
over a one week period:
y = (27 + 18 + 21 + 25 + 21 + 23 + 2
Solution to Exercise 1a
For each of the following examples determine
whether the sample is random and/or
representative of the target population:
a. to determine the average salary of
accountants in Sydney, all those who
respond to the graduate
Task Package X Package Y
The most common use of the Wilcoxon Signed
Rank test is to test differences for paired data.