If Z is a standard normal variable, find the
probability.
- The probability that z is less than 0.8.
-
0.7881 b. 0.2119 c. 0.4681 d. 0.5319
- The probability that z lies between 0.61 and 2.25.
-
0.7413 b. 0.2831 c. 0.2587 d. 0.7169
- The probability that z is greater than -2.47.
-
0.0068 b. 0.0685 c.
0.9932 d. 0.9315
- 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.
-
-
1.37 b. 1.48 c. 1.26 d. 1.01
- 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.
-
-
1.32 b. 0.13 c. -0.13 d. 0.5517
- The graph below shows a standard normal distribution. Find the
area of the shaded region.
-
-
0.8907 b. 0.8485 c. 0.8708 d. 0.1292
- 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.
-
-1.41 b. 1.41 c. -1.96 d. 1.96