Stats Final- Exam 2 material
The expected value of a discrete random variable a. is the most likely or highest probability value for the random variable b. will always be one of the values x can take on, although it may not be the highest probability value for the random variable c. is the average value for the random variable over many repeats of the experiment d. is the value it is expected to assume in the next trial
c.
Which of the following is NOT a characteristic of the normal probability distribution? a. symmetry b. the total area under the curve is always equal to 1 c. 99.72% of the time the random variable assumes a value within plus or minus 1 standard deviation of its mean d. the mean is equal to the median, which is also equal to the mode
c.
The probability density function for a uniform distribution ranging between 2 and 6 is a. 4 b. undefined c. any positive value d. 0.25
d.
A continuous random variable may assume a. any numerical value in an interval or collection of intervals. b. finite number of values in a collection of intervals c. an infinite sequences of values d. only the positive integer values in an interval
a.
Sampling distribution of (x̄) is the a. probability distribution of the sample mean b. probability distribution of the sample proportion c. mean of the sample d. mean of the population
a.
The probability that a continuous random variable takes any specific value a. is equal to zero b. is at least 0.5 c. depends on the probability density function d. is very close to 1.0
a.
The uniform and normal distribution a. are all continuous probability distributions b. are all discrete probability distributions c. can be either continuous or discrete, depending on the data d. are all the same distributions
a.
In a standard normal distribution, the a. mean and the standard deviation are both 1 b. mean is 0 and the standard deviation is 1 c. mean is 1 and the standard deviation is 0 d. mean and the standard deviation can have any value
b.
The center of a normal curve a. is always equal to zero b. is the mean of the distribution c. cannot be negative d. is the standard deviation
b.
The life expectancy of a particular brand of tire is normally distributed with a mean of 40,000 and a standard deviation of 5,000 miles. What percentage of tires will have a life of 35,000 to 45,000? a. 31.73% b. 68.27% c. 50% d. 95%
b.
As the sample size increases, the a. standard deviation of the population decreases b. population mean increases c. standard error of the mean decreases d. standard error of the mean increases
c.