Graph the density function f(x)=kx²(0≤x≤5; k suitable) and the distribution function.

According to the IRS, a particular group of taxpayers received a mean refund of $1,600. The distribution of tax refunds follows a normal distribution with a standard deviation of$850. Using this find whether ninety-five percent of the refunds are for less than what amount?

Z is the standard normal distribution. Find the indicated probabilities. $P(-1.71 \leq Z \leq 1.71)$

Given a normal distribution with $\mu=100$ and $\sigma=10$, what is the probability that $X<70$ ?

Find the indicated probability using the geometric distribution. Find P(5) when p = 0.09.

A normal distribution has a mean of 61 and a standard deviation of 15. What is the median?

Z is the standard normal distribution. Find the indicated probabilities. $P(-1.71 \leq Z \leq 0.23)$

Find the percentage of all values in a normal distribution for each z-score.

$$z \leq - 2.26$$

Find the indicated probability using the geometric distribution. Find P(8) when p = 0.28.

Find the mean and variance of the random variable X with probability function or density f(x).

$$f(x)=4e^{-4x}(x≥0)$$

Z is the standard normal distribution. Find the indicated probabilities. $P(0.5 \leq Z \leq 1.5)$

Find the percentage of all values in a normal distribution for each z-score.

$$z \leq 0.48$$

Z is the standard normal distribution. Find the indicated probabilities. $P(0.71 \leq Z \leq 1.82)$

Find the percentage of data items in a normal distribution that lie between z=-2.2 and z=-0.3.