Math Answers

 The intelligence quotients (IQs) of 16 students from one area of a city showed a mean of 107 and a standard deviation of 10, while the IQs of 14 students from another area of the city showed a mean of 112 and a standard deviation of 8. What would be the ‘ t ’ value to test whether there is a significant difference between the IQs of the two groups at significance level 0.01?

a. 2.56

b. 1.45

c. 3.45

d. 2.22

Given an example of an elliptic partial differential equation of 2nd order,

justifying your answer

The relation R on the set A={1,2,3,4,5}is defined by the rule (a,b) €R if 3|a-b|

Prove that the function f(x)= cosx-cos3x is periodc

The weight of teenagers in Barangay Payapa approaches a normal distribution with a mean of 52.9 kg and a standard deviation of 7.2 kg. If a teenager is a chosen at random from Barangay Payapa, what is the probability that his/her weight is above 48.5 kg?

1. Consider the following contingency table analyzing the relationship between major and mathematics score.

Column Variables

Row Variables

(L)

 (B)

(M)

Natural Sciences (N)

50

80

80

Social Sciences (S)

60

70

80

If there is a random selection of one student, determine the following probabilities:

     a. P(N)     b. P(B)     c. P(N Ո L)      d. P(M Ս S)      e.  P(B|N)

In testing a certain kind of truck tire over a rugged

terrain, it is found that 25% of the trucks fail to

complete the test run without a blowout. Of the next

15 trucks tested, find the probability that a) From 3

to 6 have blowouts; b) Fewer than 4 have blowouts;

C) More than 5 have blowouts.

If a given score is at the 30th percentile for reference group A and the same score is at the 60th percentile for reference group B, how do the two groups compare in terms of performance

An experiment has a binary outcome. Either success or failure. The probability of success is always 0.15. Suppose that the experiment is repeated 30 times.

a. Find out the probability that there are exactly 10 successes. 

b. Calculate the same probability using a Normal Approximation. Is the approximation good? If so why? If not why not?

A supervisor at an electric bulb factory examines bulbs produced in the factory for defects. She usually finds that there are 14 defective bulbs in a week (7 days).

a. What is the probability that there are exactly 3 defective bulbs in one day?

b. What is the probability that there are less than 5 defects in a day?

c. Suppose the supervisor joins work, find the probability that 72 hours go by before she discovers her first defective bulb.