ECON exam 2: Unit 5

True

A random variable is more likely to be close to a value that has a large density than to a value that has a small density true or false

C. A point on the horizontal axis

A single possible value for a continuous random variable is represented on a graph of the density function by A. A point on the density curve. B. A segment on the density curve. C. A point on the horizontal axis. D. A segment of the horizontal axis. E. An area below the density curve.

True

On average, a jelly bean weight is .04 ounces. Suppose 1,000 random jelly beans were put in a bowl. The probability that the weight of the 1,000 jelly beans would be between 38 and 41 ounces is less than the probability it would be between 35 and 45 ounces True or false

False

On average, a jelly bean weight is .04 ounces. Suppose 1,000 random jelly beans were put in a bowl. There is zero probability that the 1,000 jelly beans would weigh less than 39 ounces. true or flase

B. One

On average, a jelly bean weight is .04 ounces. Suppose 1,000 random jelly beans were put in a bowl. What is the probability that the weight of the 1,000 jelly beans would be between zero ounces and five tons? a. Less than zero b. one c. zero d. more than zero but less than 0.50 e. more than 0.50 but less than one

C. Zero

On average, a jelly bean weight is .04 ounces. Suppose 1,000 random jelly beans were put in a bowl. What is the probability the 1,000 jelly beans would weigh exactly 40 ounces? a. less than zero b. one c. zero d. more than zero but less than .50 e. greater than or equal to .50 but less than one

False

The number of girls in a randomly chosen family with four children is a continuous random variable. true or false

False

The number of questions you get right on your next exam is a continuous random variable. true or false

False

The probability of a continuous random variable equaling any specific value is given by its density. true or false

True

The weight of a bowl of jelly beans is a continuous random variable. True or false

False

There are minimum and maximum values for the normal distribution. True or false

True

There is more than one normal distribution. true or false

False

There is no single value of a normally distributed random variable that has a non-zero density. true or false

True

There is no single value of a normally distributed random variable that has a non-zero probability. true or false

Zero

What is the probability that the random variable has one particular value

Uniform distribution

Whenever the probability is equally likely, (proportional to the length of the interval) the random variable falls under which type of distribution

wider, flatter

a larger value of standard deviation results in what type of normal distribution curve

standard normal probability distribution

a random variable with a normal distribution mean of 0 and a standard deviation on 1 is said to have..

unbounded

any values between plus and minus infinity means the variable is

True

density is not probability true or false

bounded

must have values between two intervals means that the variable is

standard deviation and mean

the entire family of normal distribution are differentiated by two parameters what are they?

mean

the highest point on the bell curve is located at which: mean, median, or mode

1

the total area under the normal distribution curve is equal to what?

true

true or false: the normal distribution graphs are symmetrical

Uniform, normal, exponential

what are the three continuous probability distributions

standard deviation

what determines how flat and wide a normal distribution curve is

bell shaped curve

what is the shape of a normally distributed graph

68.3

what percentage of the values of a normal random variable are within plus or minus one standard deviation of its mean

99.7

what percentage of the values of a normal random variable are within plus or minus three standard deviations of its mean

95.4

what percentage of the values of a normal random variable are within plus or minus two standard deviations of its mean

less than

z-tables are meant for areas to the left of the probability making it work for probability questions concerning: greater than or less than

standard deviation

σ

mean

υ stands for what?

True

The amount of rain that will fall next week is a continuous random variable. True or false

B. Must equal one

The area under an entire density curve A. Equals the value of the random variable. B. Must equal one. C. Can differ for different continuous random variables.

True

The breaking strength of a randomly chosen floor support is a continuous random variable. true or false