Answer:
0.1666
Step-by-step explanation:
A researcher records the following response times to a visual stimulus: 23 ± 3.1 ( M ± SD) s. Assuming these data are normally distributed, what is the probability that participants responded in 20 s or less
z=X-U/SD
z=(20-23)/3.1
z=-0.9677
checking the negative part of the z score table. we go to
-0.97
that is -0.9 under 0.07
the value we get is 0.1666
P(x<20) means that P(z<-0.97)
0.1666
