Bernoulli sequences and the binomial distribution
Continuous Random Variables
Sampling and estimation
Normal Distribution
Random Questions
100

A fair die is to be rolled 90 times. If x is the number of times a six is observed then the expected value of

X,E(X)

, is equal to:


What is 15?

100

If a random variable X has a probability density function:

the mean of X is:

What is 3.125?

100

In order to estimate the proportion of teenagers in Australia who smoke, a researcher selected a random sample of 200 teenagers and found that 25% of them smoked. This percentage is an example of a:

What is a sample statistic?

100

Pr(Z<−1.983), where Z is a standard normal random variable is closest to

What is 0.0237?

100

The area of triangle LMN, in 

cm^2 is:

What is 

15 sin 40^o

200

Suppose that X is the number of female children born into a family. If the distribution of X is binominal, with probability of success of 0.48, then the probability that a family with five children will have two female children is:

What is 

5C2(0.48)^2(0.52)^3?

200

A random variable X has a probability density function as shown:




the value of k is:

What is 5?

200

A bag contains 4 black balls and three blue balls. If a random sample of three balls is taken from the bag, without replacement, the possible values of the sample proportion of the blue balls in the sample are:

What is 

200

If a random variable XX is normally distributed with a mean of 100 and a standard deviation of 10, then Pr(82<X<112) is closest to:

What is 0.8490?

200

Given that for f(x)=xsinx,f′(x)=sinx+xcosx, an antiderivative of xcosx is:  

xsinx+cosx

300

If the proportion of batteries that are defective is 0.0030, then the standard deviation of the number of defective batteries in a sample of size 1000 is closest to (assume a binomial distribution):

What is 1.729?

300

What's green and stands in the corner?

What is a naughty frog?

300

Suppose that 12% of the people in a certain country have red hair. If a random sample of 65 people is selected from that country, the mean and standard deviation of the proportion of people with red hair in the sample are:

What is 

300

What's the difference betweena guitar and a fish?

What is you can't tuna fish?

300

What is the sport that Mr Werth ruptured his ACL in?

What is football (the reall football)?

400

Suppose the random variable X represents the number of heads recorded when a fair coin is tossed 100 times.

The mean and the variance of X are equal to

What is E(X)=50, Var (X)=25?

400

What is 0.6?

400

If a researcher increases her sample size by a factor of 9, then the width of a 95% confidence interval would:

What is decrease by a factor of 3?

400

The weight of a certain breed of cat is normally distributed with a mean of 3.3 kg and a standard deviation of 1.0. If there are 50 cats of this breed at a cat show, approximately how many would be expected to weigh more than 4 kg?

What is 12?

400

What is 

500

For a particular binomial distribution with nn independent trials, each with probability of success p, the mean and variance are 5 and

4 1/6

 respectively. Which of the following gives the correct values for n and p?

What is n=30 and p=

2 xx 2/(3*x^2)1/6?

500

A teacher has determined that the bottom 20% of students will be asked to re-sit the maths test.  If the distribution of scores on the test is a random variable X with a probability density function:

then the maximum score for which a student will be asked to re-sit the examination is closest to:

What is 30?

500

A survey is conducted to determine the percentage of students in Year 12 who intend to go take a gap year after they finish secondary school. In a random sample of 200 students 18% indicated this intention. Determine a 99% confidence interval for the percentage of students in Year 12 who intend to take a gap year.

What is 11.0% to 25.0%?

500

Scores on an exam are known to be normally distributed, with a standard deviation of 1010. If 9% of the people who sat for the exam scored more than 75 marks, then the mean examination score is closest to

What is 62?

500

Evaluate   (no calculator)

What is 9?

Click to zoom
M
e
n
u