Reference no: EM132336135
Statistics Lab Assignment -
Begin by opening the SPSS file. You will find three variables in the file: CogLabID, rtsame, and rtdifferent. The variable labeled 'CogLabID' shows subjects' CogLab User IDs. The variable labeled 'rtsame' represents subjects' mean reaction times (rt) on congruent trials. Congruent trials are those for which the colour of the word matched the word itself (e.g., the word RED was printed in red ink). The variable labeled 'rtdifferent' represents subjects' mean reaction times (rt) on incongruent trials. Incongruent trials are those for which the colour of the word did not match the word itself (e.g., the word RED was printed in blue ink).
Using SPSS, calculate descriptive statistics on the Stroop 'rtdifferent' variable, and answer the following.
a. Report the mean
b. Report the median
c. Report the mode
d. Report the range
e. Report the standard deviation
f. Report the variance
Based on the values you reported in the preceding answers, what can you conclude about the shape (specifically, symmetry vs. skew) of the distribution of the "rtdifferent" variable? Explain your answer.
Based on your answer to part 1g, which is the most appropriate indicator of central tendency to use for descriptive purposes? Provide an explanation for your conclusion.
Using SPSS, calculate the median and standard deviation for the Stroop 'rtsame' variable, and answer the following.
Report the median.
Report the standard deviation.
Which variable has a higher median: 'rtdifferent' or 'rtsame'?
Which variable has a higher standard deviation: 'rtdifferent' or 'rtsame'?
Interpret the standard deviation of the 'rtsame' variable. [Hint: I am looking for more than "the standard deviation is a measure of variability or dispersion". A precise interpretation would make reference to the actual value of the standard deviation.]
Are you surprised by your answer to question 2d? Why or why not? [It might help to read a bit about the experiment in the CogLab manual to answer this question. If you purchased CogLab online, you can find a free PDF copy of the "Student Manual" for download at the CogLab website, under the "Help" tab.]
Using SPSS, compute a new variable reflecting participants' interference scores (the amount of interference the meaning of the words creates on subjects' reading speed). Subtract participants' reaction time (rt) on congruent trials from their rt on incongruent trials ('rtdifferent' - 'rtsame'), label the new variable 'msinterfere', and answer the following.
a. Report the mean.
b. Report the median.
c. Report the mode.
d. Report the range.
e. Report the standard deviation.
f. Report the variance.
What percentage of students were faster at responding to words in an incongruent ink colour ('rtdifferent') than to words in a congruent ink colour ('rtsame')?
Using SPSS, convert the 'msinterfere' variable scores from milliseconds to seconds (by dividing them by 1000). Call the new variable 'sinterfere'. Use SPSS to calculate the mean, median, range, and standard deviation of this new variable. Did the conversion affect the mean, median, range, and standard deviation differently? Why or why not?
Using SPSS, transform the 'msinterfere' variable scores to z scores (be sure to do this using SPSS), and answer the following.
Report the mean and standard deviation of the set of z scores. Do your answers surprise you? Why or why not?
Report subject Truong2019S-12's z-score.
Provide a precise interpretation of PSYC218Summer12's z-score. [A precise interpretation would make reference to the actual value of the z score.]
What is Truong2019S-12's percentile rank? Be sure to use SPSS to get your answer, and report the percentile rank to two decimal places. Provide a precise interpretation of this percentile rank. [A precise interpretation would make reference to the actual value of the percentile rank.]
Attachment:- Statistics Assignment Files.rar