Download practice lecture exam part1

Lecture exam part 1 - practice
The exam part 1 won’t be the same; the purpose of this document is only practicing!
The exam part 1 will based on lecture- (1-4) and seminar materials (1-4) as well!
1. Decide about the following statements whether they are TRUE or FALSE! Put an “X” sign in
the correct column!
Statement
TRUE FALSE
A confidence interval estimation is concerning about the sample
If you want to test whether a statement is true of false in the population,
hypothesis testing can be used
If you do not know the population standard deviation the task cannot be
solved, because there is no test for that situation
2. Find and circle the correct answer from the list!
If you want to compare the males and females average salaries (in the case when you do not
know anything about the population standard deviations)
a) two independent samples t-test can be applied
b) paired t-test can be applied
c) one sample t-test can be applied
d) one sample z-test can be applied
The result of a 95% confidence interval estimation about the mean of age is the following:
(24.2;25;8) years. The interpretation:
a) With 97.5% probability, the mean of age is between 24.2 and 25.8 years
b) With 95% probability, the age is between 24.2 and 25.8 years
c) With 95% probability, the mean of age is between 24.2 and 25.8 years
d) With 95% probability, the mean of age is between 24.2 and 25.8 percent
3.
There was a survey in a University about the sporting habits of students. With a help of an
online questionnaire, a sample with 150 elements was collected. Based on this sample, the
proportion of those who regularly doing sports is 70 percent.
a) Develop a 90% interval for the proportion of those who regularly doing sports!
b) Interpret the result!
4.
According to a TV commercial the price of X washing powder is lower than 2000 HUF/piece
in most retail shops.
There was a survey about unit prices of the X washing powder in several retail shops. 160
washing powders were examined in different places. Based on this sample with 160
elements, the mean of washing powder prices is 1900 HUF/piece, with a standard deviation
of 110 HUF/piece.
Can we assume at 5% significance level that the mean of washing powder prices is lower
than 2000 HUF/piece?
5.
Economist students were asked about expected beginning salaries in a survey. The results
from the sample in the following table:
Gender
Number of sample
Male
Female
200
300
Expected beginning salary, thousand
HUF/month
mean
standard deviation
240
12
230
11
(The sample standard deviations can be considered to be equal.)
Can we assume at 5% significance level that the average expected beginning salary of male
and female respondents are the same?