Search & Filtering
A survey of the National Capital Region finds the average commute time of employees on one way is 45 minutes. The Makati Chamber of Commerce feels that in their city it is greater and want to publicize this. They randomly selected 28 commuters and found the average is 50 minutes with a standard deviation of 6 minutes. At 0.05 level of significance.
A group of students got the following scores in a test: 6, 9, 12, 15, 18, and 21. Consider samples of size 3 that can be drawn from this population. List all the possible samples and the corresponding mean. Sample Mean
In statistical thinking, why P (-2<z<1) is the same as P (-2≤z≤1)?
Each time Caroline goes shopping she decides whether or not to buy fruit.
The probability that she does buy fruit is 0.6.
Independently, she then decides whether or not to buy a CD, with a probability of 0.2 that she does buy a CD.
Work out the probability that she buys fruit or buys a CD or both.
If the amount of cosmic radiation to which a person is exposed while flying by jet across the United States is a random variable having the normal distribution with mean as
4.35 mrem and standard deviation as 0.59 mrem. Find the probabilities that the amount of cosmic radiation to which a person is exposed on such a flight is:
a) Between 4.00 mrem to 5.00 mrem,
b) At least 5.50 mrem,
c) No more than 4.5 mrem.
There are 150 students in a class. The distribution if their marks in a mathematics test are as follows
Class frequency
0-9 3
10-19 10
20-29 17
30-39 x
40-49 35
50-59 y
60-69 18
70-79 10
80-89 5
90-99 2
Required
i) The value of x given that the median mark is 44.357 (2marks)
ii) The value of y given that the modal is 43.0 (2marks)
iii) Draw an ogive of the data in (a) above (3 marks)
Suppose that the average outstanding credit card balance for young professionals
is Php11,200 with standard deviation of Php 2,600. In simple random sample of
150 young professionals, what is the probability that the mean outstanding credit
card balance does not exceeds Php12,300?
QUESTION THREE
In a Competitive examination of 5000 students, the marks of the examinees in statistics were found to be distributed normally with mean 45 and standard deviations 14.
Determine the number of examinees whose marks, out of 100 were;
(i) Less than 30. 2MKS
(ii) Between 30 and 70. 2MKS
(iii) Between 60 and 80. 2MKS
(iv) More than 60. 2MKS
(v) More than 40 2MKS
Consider all the possible samples of size 2 that can be drawn without replacement from the population 1, 4, 6 and 7.
Compute the following;
a. Mean of the sampling distribution of the sample means
b. Variance of the sampling distribution of the sample means
c. Standard deviation of the sampling distribution of sample means
An individual is handover a bag filled with balls of different colours. The table below
gives the probability that a randomly chosen ball is of a specific colour, along with a
missing probability value of picking a ball of white colour.
Colour Red Yellow Green Orange Blue White
Probability 0.2 0.2 0.1 0.1 0.3 ?
Answer the following questions:
(i) What value must the missing probability be?
(ii) If a ball is drawn at random from the bag, what is the probability of each of the
following events?
I. It is either Blue or Red in colour.
II. It is notYellow in colour.
III. It is neither Orange nor White in colour.
IV. It is either Blue or Red or Yellow or Green or Orange or White.
