STA101: Statistics for Business - Quiz Scores, Confidence Interval, Regression Analysis and Hypothesis Testing

Unit: STA101 – Statistics for Business
Question 1:
a)
quiz 1 quiz 2 quiz 3 quiz 4
Mean 72 Mean 72 Mean 76 Mean 76
Median 72 Median 72 Median 72 Median 86.5
Mode 60 Mode 65 Mode 72 Mode #N/A
a) The measure agree since the mean value of the four quiz have a value that is close to the
median value. This indicates that the mode is frequent representation of the quiz marks
for every quiz.
b) In quiz 1, mean and the median show that the quiz score is normally distributed while the
mode indicates that the data is skewed on one edge.
In quiz 2, the mean and the median are equal hence the data is nominal though the mode
indicates that the data is skewed.
In quiz 3, the median and the mode are similar thus they are the best measures of central
tendency which show that data is skewed. The mean which is outliers is not a choice in
the central tendency.
In quiz 4, the mode is not applicable hence the data has no common mark for those who
attempted the test hence the data outliers. The mean and the median have values that
differ hence the data is normally distributed.
c) Quiz 1and 3 quiz is positive skewed while quiz 2 and 4 are negatively skewed.
d) In the first quiz, the students were above average and had an outlier student who scored
99. In the second quiz the students had a mark that is above average though this test
didn’t have outliers. In the third quiz, the students scored a mark that is above average
and also had outliers’ marks. In the fourth quiz, the marks of the students were distributed
from the least mark 10 to highest mark of 98.
Question 2:
a) 90 % CI for almonds
p value=0.19
standard error=1.645∗√ ¿) =0.0645
0.1255< p< 0.2545
b) Normality means
c) Sample size that would have an error of -+ 0.03
n=
[ z
E ] 2
∗pq
n=¿] ^2*0.19*0.81= 462.65
n=463
The sample size is 463
d) Testing show that the product is being marketed to the surrounding. The product can now
be determined through the price which determines the sound quality.
Question 3