Exam 7: Continuous Probability Distributions

What happens to the shape, mean, and variance of a Student t distribution as the degrees of freedom increase?

A national standardized testing company can tell you your relative standing on an exam without divulging the mean or the standard deviation of the exam scores.

IT Graduates Salary The recent average starting salary for new college graduates in IT systems is $47,500. Assume salaries are normally distributed with a standard deviation of $4,500. {IT Graduates Salary Narrative} What percent of starting salaries are no more than $42,250?

A continuous random variable X has a uniform distribution between 5 and 25 (inclusive), then P ( X = 15)= 0.05.

Which of the following distributions can take on negative values?

The variance of a Student t random variable with v degrees of freedom ( v > 2)is always greater than 1.

Suppose X has a normal distribution with mean 10 and standard deviation 2. The probability that X is less than 8 is equal to the probability that Z is less than ____________________.

The mean of a Student t distribution is ____________________.

{Electronics Test Narrative} Find the probability that a student will take more than 60 minutes to finish the test.

Tanner took a statistics test whose mean was 80 and standard deviation was 5. The total points possible was 100. Tanner's score was 2 standard deviations below the mean. What was Tanner's score, rounded to the nearest whole number?

If a point y lies outside the range of the possible values of a random variable X , then f(y)must equal zero.

The mean of the standard normal distribution is ____________________ and the standard deviation is ____________________.

Subway Waiting Time At a subway station the waiting time for a subway is found to be uniformly distributed between 1 and 5 minutes. {Subway Waiting Time Narrative} What is the probability density function for this uniform distribution?

A(n)____________________ random variable is one that assumes an uncountable number of possible values.

What number corresponds to t _0.05,10?

The 10^th percentile of a Z distribution has 10% of the Z -values lying above it.

Z _.025 is the value of Z such that the area to the ____________________ of Z is .9750.

Continuous probability distributions describe probabilities associated with random variables that are able to assume any finite number of values along an interval.

The shape of the ____________________ distribution is similar to a normal distribution, except it has more area in the tails.

Since there is an infinite number of values a continuous random variable can assume, the probability of each individual value is virtually 0.