19 2 points Any given normal distribution is completely defined by which of the following? the mean and standard deviation of the variable O the line of symmetry for the curve O the standard deviation and the variance of the variable O the total area under the curve 20 2 points There is a 25% chance that a visitor to an animal shelter will adopt a dog. Out of 20 visits, what is the variance for the number of dogs that would be adopted? O 1.88 O 3.75 O 1.94 O 5.0 21 2 points Suppose that X is a normally distributed random variable with a mean of 90 and a standard deviation of 18. The area between 72 and 90 will be the area between 90 and 108. O less than O exactly the same greater than OO cannot be determined 22 2 points Routine physical examinations are conducted annually as part of a health service program for the employees. It was discovered that the probability that an employee needed corrective shoes was .09, the probability that an employee needed major dental work was .23, and the probability that an employee needed both corrective shoes and major dental work was .04. What is the probability that a randomly selected employee will need to address at least one of the two health issues? O .36 .32 .28 .04 23 2 points Let the random variable X represent the number of cars in line at a fast food drive thru. Assume X has the following probability distribution: Value of X 1 2 3 4 .5 6 Probability 0.20 0.20 0.30 0.15 0.10 0.05 Find the probability that the number of cars in line is an even number. O .50 .55 ..40 O .35