Statistics and Probability Answers

Consider the measures below and answer questions 1 and 2.
(A) µ
(B) σ
(C) ā
(D) s

Question 1

Which measures are considered as population parameters?

(1) Only A.
(2) Only B.
(3) Only A and B.
(4) Only A, B and C.
(5) Only C and D.

Question 2

Which measures are considered as sample statistics?

(1) Only A.
(2) Only B.
(3) Only A and B.
(4) Only A, B and C.
(5) Only C and D.

Question 26

Consider the sample space S = {1, 2, 3, 4, 5} and let A be a set of numbers less or equal to 4 and B be set of numbers greater than 4. Both A and B are subsets of S.

Which one of the following statements is incorrect?

(1) A = {1, 2, 3, 4} and B = {5}
(2) P(A) = 4/5
(3) P(B) = 1/5
(4) Events A and B are mutually exclusive.
(5) Events A and B are independent.

Table below shows FK and what postings are about. Answer question 27 to 30.

C P SS Total
SM 1800 700 515 3015
TM 485 350 150 985
Total 2285 1050 665 4000

Q 27
Which statement is incorrect
1) P(SM)=0.75
2) P(SM^C)=P(TM)=0.25
3) P(C)=0.57
4) P(SS)=0.17

Q 28
Which statement is incorrect
1) P(C & SS)=0
2) P(C & SM)=0.45
3) P(C & TM)=0.12
4) P(SM | C)=0.60
5) P(SM | SS)=0.77

Q 29
Which statement is incorrect
1) SM &C are dependent
2) SM &SS are dependent
3) TM & SS are independent
4) SM &TM are mutually exclusive
5) C & P are mutually exclusive

Q 30
What is the probability that FK posting is about a SS given that the source is TM
1) 0.25
2) 0.23
3) 0.17
4) 0.15
5) 0.04

Question 17

The sum of deviations about the mean is always?

(1) Zero.
(2) Total standard deviation.
(3) Positive.
(4) Negative.
(5) Range.

Question 18

If the population variance is 4, then the population standard deviation must be?

(1) 4
(2) 16
(3) 2
(4) 0
(5) 12


Question 25

Which one of the following statements is incorrect?

(1) If an event has a probability of 0:25, then the event has a 25% chance of occurring.
(2) A probability is a chance of an event not occurring.
(3) When two events are mutually exclusive, they cannot occur together.
(4) When two events are independent, they can occur together but they do not influence each
other.
(5) The intersection of two events A and B is denoted as P.A and B/.

Question 15

Which one of the following statements is incorrect?

(1) Graphs provide an overview of the profile of random variables.
(2) Descriptive statistics identify the location, dispersion and shape of the data.
(3) The location (central tendency) refers to where the data values are spread about the middle
values.
(4) Three commonly used central location statistics are: average, median and mode.
(5) The second quartile equals the median.


Question 16

The middle value in an ordered array of numbers is the:

(1) Midpoint.
(2) Median.
(3) Mean.
(4) Mode.
(5) None of the above.

Table below shows a numeric frequency distribution of number of likes on a Facebook fake
news post. Use this information to answer questions 13 and 14.

Likes Cumulative Frequency
400 < 800 7
800 < 1200 21
1200 < 1600 26
1600 < 2000 29
2000 < 2400 30

Question 13

The relative frequency for class 800 < 1200 is:
(1) 0.47
(2) 0.19
(3) 21
(4) 0.7
(5) 14

Question 14

What is the frequency of class 2000 < 2400?
(1) 0.03
(2) 30
(3) 1
(4) 0.97
(5) None of the above.

Consider Table and answer question 8 to 11

SMP FNPC
Facebook 1424
Twitter 988
WhatsApp 888

Q 8
Which statement is correct
1) FNPC is qualitative nominal variable
2) FNPC is categorical variable measured on an ordinal scale
3) FNPC is quantitative discrete variable
4) FNPC is quantitative continuous variable measured on a ratio

Q 9
Table is referred to as a
1) Frequency distribution
2) Relative frequency
3) Frequency
4) Cumulative frequency

Q 10
Appropriate graphical form to summarize the data in Table is
1) Histogram
2) Scatter plot
3) Bar Chart
4) Frequency distribution

Q 11
Which statement is incorrect
1) Relative frequency of facebook is 1424
2) Percentage frequency if facebook is 43:15%
3) Relative frequency of Twitter is 0:30
4) Percentage frequency of WhatsApp is 26:91%

Question 6

Consider the two variables below. (News Medium and Social Media Platform).

News Medium Social Media Platform
Traditional Media Facebook
Social Media Twitter
WhatsApp

Which one of the following statements is incorrect?
(1) News medium is qualitative variable.
(2) News medium has an nominal scale of measurement.
(3) Social Media platform is a quantitative variable.
(4) Social Media platform has a nominal scale of measurement.
(5) News Medium and Social Media Platform are both categorical variables


Question 12

Consider
(A) Bar Chart
(B) Histogram
(C) Pie chart
(D) Scatter plot
(E) Stem-and-leave display

Which graphical method are most appropriate for quantitative data
(1) A and B
(2) B and D
(3) B,D and E
(4) A
(5) B

Researchers from Africa Check (a fact checking organisation) are tasked with investigating
fake news posts on Social Media. Questions 4 and 5 relates to these researchers.

Question 4

Which one of the following statements is incorrect?
(1) The position (Junior, Mid-Level and Senior) of the researcher is a qualitative nominal variable
(2) The gender of the researchers is a qualitative nominal variable.
(3) The age if the researchers is a quantitative continuous variable.
(4) The salary of the researchers is a quantitative continuous variable.
(5) None of the above.

Question 5
Which one of the following statements is incorrect with regard to scales of measurements?
(1) Researcher’s position has an ordinal scale of measurement.
(2) Researcher’s gender has a nominal scale of measurement.
(3) Researcher’s age has a ratio scale of measurement.
(4) Researcher’s salary has a ratio scale of measurement.
(5) None of the above.

Question 3

Which one of the following statement is incorrect?

(1) Quantitative variables can either be discrete or continuous.
(2) Qualitative variables used labels to describe attributes.
(3) The mean, median and mode can be determined for a quantitative variable.
(4) The mean cannot be determined for a qualitative variable.
(5) None of the above.


Question 7

Which one of the following statements in incorrect?

(1) The number of likes a fake news post received is a quantitative discrete variable.
(2) The number of retweets a fake news post received is a quantitative discrete variable.
(3) The number of mentions of fake news tweet is a quantitative continuous variable.
(4) The duration in hours it takes a fake news post to go viral is a quantitative continuous variable.
(5) None of the above.