Introductory Statistics Assignment -

Questions 1 to 15 are multiple-choice questions.

Q1. You asked 5 of your classmates about their height. On the basis of this information, you stated that the average height of all students in your university is 5 feet and 6 inches. This is an example of:

A) descriptive statistics 

B) inferential statistics

C) parameter    

D) population

2. In statistics, a population consists of:

A) all people living in a country

B) all people living in the area under study

C) all subjects or objects whose characteristics are being studied

D) none of the above

Q3. In statistics, a sample means:

A) people living in one city only

B) a portion of the population

C) all items under investigation 

D) none of the above

Q4. In statistics, conducting a census means:

A) making decisions based on sample results

B) checking if a variable is qualitative or quantitative

C) collecting information from all members of the population

D) none of the above

5. In statistics, a representative sample is the sample that:

A) contains the characteristics of the populations as closely as possible

B) represents the results of a sample exactly

C) contains all people living in a area

D) none of the above

Q6. Which of the following is not an example of primar.), data?

A) Data published by the Central Statistical Office of Trinidad and Tobago

B) Data published by the Trinidad and Tobago Stock Exchange

C) Data published by the Central Bank of Trinidad and Tobago

D) None of the above

Q7. When every possible sample of size n has the same chance of being selected, this is called:

A) simple random sampling        

B) stratified random sampling

C) cluster sampling         

F) quota sampling

Q8. When a sample is divided into mutually exclusive sets, and then a simple random sample is drawn from each set, this is called:

A) simple random sampling        

B) stratified random sampling

C) cluster sampling         

D) convenience sampling

Q9. The best type of chart for comparing two sets of categorical data is:

A) a line chart   

B) a pie chart

C) a histogram  

D) a bar chart

Q10. The most appropriate type of chart for determining the number of observations at or below a specific value is:

A) a histogram  

B) a pie chart

C) a. box-and-whisker diagram 

D) a ogive

Q11. Since the population is always larger than the sample, the population mean:

A) is always larger than the sample mean

B) is always smaller than the sample mean

C) is always larger then or equal to the sample mean

D) can be smaller than, or larger than, or equal to the sample mean

Q12. Which of the following measures cannot be easily approximated from a box-and-whisker diagram?

A) the range      

B) the interquartile range

C) the standard deviation            

D) none of the above

Q13. The average score for a class of 30 students was 75. The 20 males students in the class averaged 70. The female students in the class averaged:

A) 75     

B) 85     

C) 65     

D) 80

14. Expressed in percentiles, the interquartile range is the difference between the:

A) 10% and 60% values 

B) 45% and 95% values

C) 25% and the 75% values         

D) 15% and the 65% values

Q15) Which one of the following statements is true?

A) when the distribution is skewed to the left, mean median: mode

B) when the distribution is skewed to the right mean < median < mode

C) when the distribution is symmetric and  modal, mean = median = mode

D) when the distribution is symmetric and bimodal mean = median = mode

Questions 16 to 18 are based on the following data, which are the ages in years of the sample of 25 employees from a government department:

31           43           56           23           49

42           33           61           44           28

48           38           44           35           40

64           52           42           47           39

53           27           36           35           20

16) Construct a stem-and-leaf diagram for the ages.

17) From the stem-and-leaf diagram constructed in Question 16:

(a) Find the median age

(b) Find the lower quartile of the ages

(c) Find the 60% percentile of the ages

(d) Compute the range of the data

Q18) (a) Construct a frequency distribution for the data, using five class intervals and the value 20 as the lower limit of the first class.

(b) Calculate the mean and the variance of the ages from the frequency distribution constructed in part (a).

Q19) The marks of a sample of students doing ECON1005 were processed using MINITAB. The outputs obtained are shown below:

(a) What is the modal score of the ECON1005 marks?

(b) Comment on the relative performance of the male and female students who did ECON1005.

(c) Calculate the quartile deviation for the marks in ECON1005.