Answer Happy

A driver’s reaction time to visual stimulus is normally
distributed with a mean of 0.4 seconds and a standard deviation of
0.05 seconds. (a) What is the probability that a reaction requires
more than 0.5 seconds? (b) What is the probability that a reaction
requires between 0.4 and 0.5 seconds? (c) What reaction time is
exceeded 90% of the time?
STANDARD NORMAL TABLE (2) Entries in the table give the area under the curve between the mean and z standard deviations above the mean. For example, for z = 1.25 the area under the curve between the mean (0) and z is 0.3944. z 0.00 0.01 0.02 0.03 0.04 0.05 0.0 0.0000 0.0040 0.0080 0.0120 0.0160 0.0190 0.1 0.0398 0.0438 0.0478 0.0517 0,0557 0.0596 0.2 0.0793 0.0832 0.0871 0.0910 0.0948 0.0987 0.3 0.1179 0.1217 0.1255 0.1293 0.1331 0.1368 0.4 0.1554 0.1591 0.1628 0.1664 0.1700 0.1736 0.5 0.1915 0.1950 0.1985 0.2019 0.2054 0.2088 0.6 0.2257 0.2291 0.2324 0.2357 0.2389 0.2422 0.7 0.2580 0.2611 0.2642 0.2673 0.2704 0.2734 0.8 0.2881 0.2910 0.2939 0.2969 0.2995 0.3023 0.9 0.3159 0.3186 0.3212 0.3238 0.3264 0.3289 1.0 0.3413 0.3438 0.3461 0.3485 0.3508 0.3513 1.1 0.3643 0.3665 0.3686 0.3708 0.3729 0.3749 1.2 0.3849 0.3869 0.3888 0.3907 0.3925 0.3944 1.3 0.4032 0.4049 0.4066 0.4082 0.4099 0.4115 1.4 0.4192 0.4207 0.4222 0.4236 0.4251 0.4265 1.5 0.4332 0.4345 0.4357 0.4370 0.4382 0.4394 1.6 0.4452 0.4463 0.4474 0.4484 0.4495 0.4505 1.7 0.4554 0.4564 0.4573 0.4582 0.4591 0.4599 1.8 0.4641 0.4649 0.4656 0.4664 0.4671 0.4678 0.4713 0.4719 0.4726 0.4732 0.4738 0.4744 2.0 0.4772 0.4778 0.4783 0.4788 0.4793 0.4798 2.1 0.4821 0.4826 0.4830 0.4834 0.4838 0.4842 2.2 0.4861 0.4864 0.4868 0.4871 0.4875 0.4878 2.3 0.4893 0.4896 0.4898 0.4901 0.4904 0.4906 2.4 0.4918 0.4920 0.4922 0.4925 0.4927 0.4929 2.5 0.4938 0.4940 0.4941 0.4943 0.4945 0.4946 2.6 0.4953 0.4955 0.4956 0.4957 0.4959 0.4960 2.7 0.4965 0.4966 0.4967 0.4968 0.4969 0.4970 2.8 0.4974 0.4975 0.4976 0.4977 0.4977 0.4978 2.9 0.4981 0.4982 0.4982 0.4983 0.4984 0.4984 3.0 0.4987 0.4987 0.4987 0.4988 0.4988 0.4989 3.1 0.4990 0.4991 0.4991 0.4991 0.4992 0.4992 3.2 0.4993 0.4993 0.4994 0.4994 0.4994 0.4994 3.3 0.4995 0.4995 0.4995 0.4996 0.4996 0.4996 3.4 0.4997 0.4997 0.4997 0.4997 0.4997 0.4997 0.06 0.07 0.08 0.09 0.0239 0.0279 0.0319 0.0359 0.0636 0.0675 0.0714 0.0753 0.1026 0.1064 0.1103 0.1141 0.1406 0.1443 0.1480 0.1517 0.1772 0.1808 0.1844 0.1879 0.2123 0.2157 0.2190 0.2224 0.2454 0.2486 0.2517 0.2549 0.2764 0.2794 0.2823 0.2852 0.3051 0.3078 0.3106 0.3133 0.3315 0.3340 0.3365 0.3389 0.3554 0.3577 0.3529 0.3621 0.3770 0.3790 0.3810 0.3830 0.3962 0.3980 0.3997 0.4015 0.4131 0.4147 0.4162 0.4177 0.4279 0.4292 0.4306 0.4319 0.4406 0.4418 0.4429 0.4441 0.4515 0.4525 0.4535 0.4545 0.4608 0.4616 0.4625 0.4633 0.4686 0.4693 0.4699 0.4706 0.4750 0.4756 0.4761 0.4767 0.4803 0.4808 0.4812 0.4817 0.4846 0.4850 0.4854 0.4857 0.4881 0.4884 0.4887 0.4890 0.4909 0.4911 0.4913 0.4916 0.4931 0.4932 0.4934 0.4936 0.4948 0.4949 0.4951 0.4952 0.4961 0.4962 0.4963 0.4964 0.4971 0.4972 0.4973 0.4974 0.4979 0.4979 0.4980 0.4981 0.4985 0.4985 0.4986 0.4986 0.4989 0.4989 0.4990 0.4990 0.4992 0.4992 0.4993 0.4993 0.4994 0.4995 0.4995 0.4995 0.4996 0.4996 0.4996 0.4997 0.4997 0.4997 0.4997 0.4998 1.9