21. Payne (2001) gave participants a computerized task in which they first see a

face and then a picture of either a gun or a tool. The task was to press one button
if it was a tool and a different one if it was a gun. Unknown to the participants
while they were doing the study, the faces served as a “prime”
(something that starts you thinking a particular way) and half the time were of a
black person and half the time of a white person. Table 2–8 shows the means
and standard deviations for reaction times (time to decide if the picture is of a
gun or a tool) after either a black or white prime. (In Experiment 2, participants
were told to decide as fast as possible.) Explain the results to a person who has
never had a course in statistics. (Be sure to explain some specific numbers as
well as the general principle of the mean and standard deviation.)
8 Mean Reaction Times (in Milliseconds) in Identifying
Guns and Tools in Experiments 1 and 2

Prime
Black White
Target M SD M SD
Experiment 1
Gun 423 64 441 73
Tool 454 57 446 60
Experiment 2
Gun 299 28 295 31
Tool 307 29 304 29

Since you don't indicate what test(s) you are using, it is harder to explain.

Is the variation in means or standard deviations significant or due to chance? That would be a good starting point.

The teacher wants to know if you understand what is happening. If you can explain something clearly to others, this indicates that you understand. Do you?

I hope this helps.

In this study by Payne (2001), participants were given a computerized task where they had to quickly identify whether a picture shown on the screen was either a gun or a tool. However, what the participants did not know was that before each picture, they were shown a face, which served as a "prime" to influence their thinking in a particular way. These faces could be either of a black person or a white person, and they were shown an equal number of times.

The table provided shows the mean reaction times (in milliseconds) and standard deviations for identifying guns and tools after either a black or white prime. Let's take a closer look at the specific numbers and what they mean.

In Experiment 1, the mean reaction time for identifying guns after a black prime was 423 milliseconds, with a standard deviation of 64 milliseconds. This means that, on average, it took the participants 423 milliseconds to decide if a picture was a gun after seeing a black face as the prime. The standard deviation of 64 indicates that there was some variability in the participants' reaction times, with some being faster or slower than the average.

Similarly, the mean reaction time for identifying guns after a white prime in Experiment 1 was 441 milliseconds, with a standard deviation of 73. This means that, on average, it took the participants slightly longer (441 milliseconds) to make the same decision when a white face was shown as the prime. Again, the standard deviation of 73 shows variability in the participants' reaction times.

Moving on to the tool identification, in Experiment 1 the mean reaction time after a black prime was 454 milliseconds, with a standard deviation of 57. After a white prime, the mean reaction time for identifying tools was 446 milliseconds, with a standard deviation of 60.

In Experiment 2, where participants were specifically instructed to respond as quickly as possible, the mean reaction time for identifying guns after a black prime was 299 milliseconds, with a standard deviation of 28. After a white prime, the mean reaction time was 295 milliseconds, with a standard deviation of 31.

For tool identification in Experiment 2, the mean reaction time after a black prime was 307 milliseconds, with a standard deviation of 29. After a white prime, the mean reaction time was 304 milliseconds, with a standard deviation of 29.

Now, the general principle of the mean and standard deviation is that the mean represents the average value of a set of data, while the standard deviation indicates the spread or variability of the data points around the mean. In this study, the mean reaction times give us an idea of the average time it took participants to make the identification, while the standard deviations give us an understanding of the range and variability of their reaction times.

In summary, these results suggest that there may be some differences in reaction times based on the race of the prime face shown before the picture of the gun or tool. However, further analysis and statistical tests would be needed to determine if these differences are statistically significant and not due to random variation.