STA1610 ASSESSMENT 5 SEM 2 OF 2023 EXPECTED QUESTIONS AND ANSWERS
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Course
Introduction to Statistics (STA1610)
Institution
University Of South Africa (Unisa)
THIS DOCUMENT CONTAINS STA1610 ASSESSMENT 5 SEM 2 OF 2023 EXPECTED QUESTIONS AND ANSWERS. USING IT CORRECTLY WILL HELP YOU SCORE ABOVE 80% IN THIS KEY ASSESSMENT.
Started on Thursday, 21
September 2023,
6:17 PM
State Finished
Completed on Thursday, 21
September 2023,
7:23 PM
Time taken 1 hour 6 mins
Marks 16.00/20.00
Grade 80.00 out of
100.00
Question 1 Which one of the following statements is incorrect about a chi-square test of independence between two variables?
Incorrect
M ark 0.00 out of a. The alternative hypothesis is that the two variables are independent of each other.
2.00
b. The expected frequency for each cell is equal to (row total × column total) ÷ ÷ n , where n is the sample size.
c. The test statistic has (r-1)(c-1) degrees of freedom, where r is the number of rows and c is the number of columns.
d. The two variables are categorical.
e. If the observed and the expected frequency for each cell are equal, then the test statistic will be equal to zero.
Question 2 Now consider a contingency table with 5 rows and 2 columns (in a chi-square test of independence). If the level of significance is 1%, what is the critical value?
Correct
M ark 2.00 out of a. 13.277
2.00
b. 18.307
c. 18.549
d. 34.805
e. 24.996
,Question 3 Consider the contingency table below to test the independence between the distance from home to school and the school level. What is the expected frequency of primary
Correct school learners travelling between 3km and 6km from home to school? Choose the correct answer from the list of options below.
M ark 2.00 out of
2.00
a. 122
b. 211
c. 0.12
d. 221
e. 119
Question 4 The following 2×3 contingency table contains observed frequencies and expected frequencies (in the brackets) from a sample of 348 observations. Calculate the chi-square test
Correct statistic required to test the independence of row and column variables and choose the correct answer from the list of options below.
M ark 2.00 out of
2.00
a. 6.36
b. 9.40
c. 3.27
d. 2.54
e. 10.36
, Question 5 The test statistic for the test of independence from question 5 has be calculated as 1.56. If the level of significance is 10%. Which one of the statements about the decision and
Correct hypothesis is correct?
M ark 2.00 out of
2.00
a. The test statistics is less than the critical value, we therefore do not reject the null hypothesis.
b. The test statistics is greater than the critical value, we therefore do not reject the null hypothesis.
c. The test statistics is less than the critical value, we therefore reject the null hypothesis.
d. The test statistics is greater than the critical value, we therefore reject the null hypothesis.
e. The null hypothesis is that distance from home to school and school level are not independent of each other.
Question 6 Which one of the following statements is incorrect about some concepts of simple linear regression?
Correct
M ark 2.00 out of a. The least squares method estimates the regression equation by maximizing the error sum of squares (SSE).
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b. The coefficient of determination gives an indication of how well the estimated regression equation fits the data.
c. The coefficient of determination always takes on values between 0 and 1.
d. The correlation coefficient always takes on values between -1 and 1.
e. The correlation coefficient takes on the sign of the slope of the estimated regression equation.
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