Statistics and Probability Answers

I am playing a video game where an item I am after has a drop rate of 1/100. I have now had 692 chances at this item. How unlikely is that I have not yet received this item?

One wishes to investigate the hypothesis that exercise reduces systolic blood pressure. A 100 person sample from a particular sedentary population indicates that μ = 120 mm Hg with a standard deviation of 8.7 mm Hg. A sample of 33 members of the local running club have a mean systolic pressure of 113 mm Hg and a standard deviation of 9.2 mm Hg.

a. State Ha c. What do you conclude at alpha = .01?
b. State Ho

A quality audit of a bottling company showed the number of defective batches outside of the specification limits for a particular oil product. The grouped data shown in the table below indicated the number of b=defective items per unit of measurement:

Volume (ml) f
20 - < 25 1
25 - < 30 2
30 - < 35 8
35 - < 40 5
40 - < 45 3
45 - < 50 1

3.1 Complete the table under the given columns: (4)

CLASS LIMITS f CUM < f CLASS MARK (X) X f X - X ̅ (X - X ̅)2 (X - X ̅)2 f

3.2 Calculate the mean value. (2)

3.3 Calculate the standard deviation. (3)

3.4 Draw the less-than ogive graph.
Use your graph to determine the median value. (5)

3.5 Calculate the 80th percentile value. (3)

3.6 Use the values from 3.2 and 3.4 to comment on the nature if the distribution.
Give a reason for your answer.

2.3 Given the following ordered arrangement of ungrouped data:

114 118 121 124 127 131 134 137
116 119 122 125 127 131 135 137
116 120 123 125 128 133 135 141
116 121 123 126 129 133 135 143
117 121 124 126 129 134 135 147

Arrange the data in a frequency distribution having the following columns:
Class boundaries, frequency, class mark.
Let the boundary values of the first class be: 110 - < 115

From the set A={3,2 √ ,23 √ ,9 √ ,7 √ },a number is selected at random. Find the probability that is a rational number

In company XYZ, 30 percent of the workers take public transportation daily to go to work.

1. In a sample of 10 workers, what is the probability that 3 workers take public transportation to work daily?

a. .900
b. .267
c. .100
d. 1.20

2.In a sample of 10 workers, what is the probability that at least 3 workers take public transportation to work daily?

a. .767
b. .383
c. .617
d. .100

3.In a sample of 10 workers, what is the probability that, at most, 2 workers take public transportation to work daily?

a. .233
b. .121
c. .383
d. .149

Customers arrive at a particular store at the rate of 30 customers per hour.

1. What is the probability of 15 customers arriving in an hour?

a. .500
b. .001
c. .617
d. .100

2. What is the probability of 10 customers arriving in a 20-minute interval?

a. .500
b. .000
c. .125
d. 1.00

3. What is the probability of at least 2 customers arriving in a 5-minute interval?

a. .257
b. .713
c. .743
d. .287

4. What is the probability of 3 customers arriving in a 5-minute interval?

a. .000
b. .214
c. .500
d. .100

a survey was conducted to measure the number of hours per week adults in the united states spend on home computers. In the survey, the number of hours were normally distributed, with a mean of 7 hours and a standard deviation of 1 hour. a survey participants is randomly selected.
a). Find the probability that the hours spent on the home computer by the participant are less than 4.5 hours per week,
b). find the probability that the hours spent on the home computer by the participant are more than 9.5 hours per week.

2 In how many ways can a committee of 5 people be chosen out of 9 people?
3 If two dies are tossed together what is the probability of having sum of 5 as the outcome.
4 If two dies are tossed together, what is the probability of having equal outcomes?
5 In how many ways can the word "HOSPITAL" be arranged?
6 In how many ways can the word "TOPO" be arranged
10 Find the standard deviation of the distribution 12,6,7,3,15,10,18,5

1 The variance of a given distribution is 25. What is the standard deviation.
2 Seven Matrons assembled for a meeting, shake hands with one another. How many handshakes take place……………….?
3 What is the evaluation of 5! ?
4 If four coins are flipped in succession, then the number of possible outcomes is…………….
5 The probabilities of a boy passing English and Mathematics tests are x and y respectively. Find the probability of the boy failing both tests.
6 Parameter is a descriptive measurement obtained from a whole………………
7 The grade of student on six examinations were 84, 91, 72, 68, 87, and 78. What is the arithmetic mean of the grades?
8 The scores of 5 students in an examination are: 6, 5, 8, 7 and 4. Find the variance.
9 The scientific method for collection, summarization, presentation, analysis and interpretation of data is called