Math Answers

IQs are designed to be N(100,225).

a. To join Mensa an IQ of 138 is required. What percentage of the population are

eligible to join?

b. A psychologist claims that any child with an IQ of 150+ is ‘gifted’. How many ‘gifted’ children would you expect to find in a school of 1800 pupils?

A random sample of n=90| kilograms of corn is obtained from a population with u =272 and sigma = 5543 . Describe the sampling distribution for the sample means by computing the mu hat x and sigma_{x} (Use the indefinite population)

The average height of students in a freshman class of a certain school has been 158.55 cm with a population standard deviation of 8.8 cm. Is there a reason to believe that there has been a change in the average height if a random sample of 51 students in the present freshman class has an average height of 154.25 cm? Use a 0.1 level of significance.

What are the given? Write only the number. :

population mean:Blank 1 cm

population standard deviation:Blank 2 cm

sample size:Blank 3

sample mean:Blank 4 cm

level of significance:Blank 5

What are the critical values? Write the positive critical value first then the negative.

z:Blank 6 andBlank 7

What is the value of the calculated z? Round your answer to the nearest hundredths.

z:Blank 8

"It is claimed that a car is driven on the average less than 28700 kilometers per year with a population standard deviation of 2100 kilometers. To test this claim, a random sample of 58 car owners are asked to keep a record of the kilometers they travelled. Would you agree with this claim if the random sample showed an average of 22500 kilometers? Use a 0.01 level of significance.

What are the given? Write only the number. :

population mean:Blank 1 km

population standard deviation:Blank 2 km

sample size:Blank 3

sample mean:Blank 4 km

level of significance:Blank 5

What is the critical value?

z:Blank 6

What is the value of the calculated z? Round your answer to the nearest hundredths.

z:Blank 7"

The average height of students in a freshman class of a certain school has been 158.55 cm with a population standard deviation of 8.8 cm. Is there a reason to believe that there has been a change in the average height if a random sample of 51 students in the present freshman class has an average height of 154.25 cm? Use a 0.1 level of significance.

What are the given? Write only the number. :

population mean:Blank 1 cm

population standard deviation:Blank 2 cm

sample size:Blank 3

sample mean:Blank 4 cm

level of significance:Blank 5

What are the critical values? Write the positive critical value first then the negative.

z:Blank 6 andBlank 7

What is the value of the calculated z? Round your answer to the nearest hundredths.

z:Blank 8

Lemuel bought bottles of food supplements at Php 1 800 each. He is planning to sell this at 15% markup on cost. At this selling price and a fixed cost of Php 40 000, how many bottles of food supplement must he sell to be able to breakeven? If he wants to earn a minimum of Php 100 000 by just selling these bottles, how many bottles must he sell?

Given the population 1,3,4,6 and 8. Suppose samples of size 3 are drawn from this population.

How many different samples can be drawn from this population?

A fair spinner has 9 equal sections: 3 red, 2 blue and 4 green.

It is spun twice.

What is the probability of not getting two consecutive blues?

The rate of increase of the population of bateria in a culture is proportional to the number of bacteria at any given instant. Assume the initial count of bacteria is 1000 and after 1 hour the amount is 1200. Find (i) the number of bacteria present immediately after 5 hours. (iii) the time lapse before the number reaches 4000

Find the maximum value of z=6x−3x2 +2y

subject to the constraint

y − x2 = 2