Question

1.  50 part-time students were asked how many courses they were taking this term. The (incomplete) results are shown below:

# of Courses	Frequency	Relative Frequency	Cumulative Frequency
1	15	0.3
2	23
3

a. Complete the table.

b. What percent of students take exactly one course? _____%

2. The five number summary of a data set was found to be:

0, 4, 11, 15, 20

An observation is considered an outlier if it is below: _____

An observation is considered an outlier if it is above: _____

3.  This data is from a sample. Calculate the mean, standard deviation, and variance.

x	27	38.2	28.4	45.7	20.6	20.1	23.6	42.1	11.3

Please show the following answers to 2 decimal places.

Sample Mean = ______

Sample Standard Deviation = ______

Sample Variance = _____ (Please use the standard deviation above for your calculation.)

Oops - now you discover that the data was actually from a population! So now you must give the population standard deviation.

Population Standard Deviation = _____

4. We are going to calculate the mean, median, and mode for two sets of data. Please show your answer to one decimal place if necessary.

Here is the first data set.

27

88

84

56

49

39

86

33

53

24

53

what is the mean (x¯) of this data set? ____

What is the median of this data set? _____

What is the mode of this data set? ____

Here is the second data set.

65

89

56

22

30

30

31

95

68

59

What is the mean (¯xx¯) of this data set? ____

What is the median of this data set? ____

What is the mode of this data set? _____

5.  E and F are mutually exclusive events. P(E) = 0.91; P(F) = 0.42. Find P(E | F) _____

6.   A special deck of cards has 3 blue cards, and 7 orange cards. The blue cards are numbered 1, 2, and 3. The orange cards are numbered 1, 2, 3, 4, 5, 6 and 7. The cards are well shuffled and you randomly draw one card.

B = card drawn is blue
O = card drawn is odd-numbered

a. How many elements are there in the sample space? _____

b. P(B) =____

7.   The table summarizes results from pedestrian deaths that were caused by automobile accidents.

Pedestrian Deaths

Driver Intoxicated?	Pedestrian Intoxicated?
	Yes	No
Yes	56	79
No	249	592

If one of the pedestrian deaths is randomly selected, find the probability that the pedestrian was intoxicated. (Round your answer to 4 decimal places.)
Probability = _______

Answer 1

#a. Complete the table.

# of Courses	Frequency	Relative Frequency	Cumulative Frequency
1	15	0.3	15
2	23	0.46	38
3	12	0.24	50
sum	50	1

#Relative frequency=frequency /Total frequency

b. What percent of students take exactly one course?

Ans: percent of students take exactly one course is =(15/50)*100=30

therefore 30 % of students take exactly one course

Ans2. The five number summary of a data set was found to be:

> x=c(0,4,11,15,20);x
[1] 0 4 11 15 20
> summary(x)
Min. 1st Qu. Median Mean 3rd Qu. Max.
0 4 11 10 15 20
> boxplot(x)$out
numeric(0)
#hence there is no outlier

Ans3:

> x=c(27,38.2,28.4,45.7,20.6,20.1,23.6,42.1,11.3);x
[1] 27.0 38.2 28.4 45.7 20.6 20.1 23.6 42.1 11.3
> mean(x)
[1] 28.55556
> var(x)
[1] 128.7428
># sd=standard deviation x
> sd=sqrt(var(x));sd

[1] 11.34649

> Sample Mean = 28.55

Sample Standard Deviation = 11.35

Sample Variance =128.7428

#Population Standard Deviation

first we find population variance

population variance=((n-1)\n)*var=(9/8)*128.7428=144.83

Population Standard Deviation =sqrt(144.83)=12.03

#Population Standard Deviation =12.03