Question

# If Z is a standard normal variable, find the probability. The probability that z is less...

If Z is a standard normal variable, find the probability.

1. The probability that z is less than 0.8.
1. 0.7881                          b.   0.2119                    c.   0.4681                     d.   0.5319
2. The probability that z lies between 0.61 and 2.25.
1. 0.7413                          b.   0.2831                    c.   0.2587                     d.   0.7169
3. The probability that z is greater than -2.47.
1. 0.0068                          b.   0.0685                    c. 0.9932                       d.   0.9315
4. The graph below shows a standard normal distribution. Find the z-score associated with the shaded area. The area of the shaded region is 0.0694.

1. 1.37                             b.   1.48                        c.   1.26                        d.   1.01
1. The graph below shows a standard normal distribution. Find the z-score associated with the shaded area. The area of the shaded region is 0.4483.

1. 1.32                             b.   0.13                        c.   -0.13                       d.   0.5517
1. The graph below shows a standard normal distribution. Find the area of the shaded region.

1. 0.8907                          b.   0.8485                    c.   0.8708                     d.   0.1292
1. The Precision Scientific Instrument Company manufactures thermometers that are supposed to give readings of  at the freezing point of water. Tests on a larger sample of these thermometers reveal that at the freezing point of water, some give readings below  (denoted by negative numbers) and some give readings above  (denoted by positive numbers). Assume that the mean reading is  and the standard deviation of the readings is . Also assume that the frequency distribution of the errors closely resembles the normal distribution. A thermometer is randomly selected and tested. Find the temperature reading corresponding to the given information.

A quality control analyst wants to examine thermometers that give readings in the bottom 2.50%. Find the reading that separates the bottom 2.50% from the others.

1. -1.41                         b.   1.41                     c.   -1.96                    d.   1.96

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