Question

An educational psychologist hypothesizes that individuals not using a word-processing grammar-checker will make more grammatical errors in a hand-written draft. At a local university, the average number of errors per page is 7 for a hand-written writing test. To investigate, a sample of university students was prohibited from using a grammar-checker for a semester. What can the psychologist conclude with α = 0.01? The data are below.

id	error
8 1 3 4 5 7 11 21 19 15 45 33 24 46 30 2	9 10 10 10 7 8 10 8 7 8 12 6 10 8 9 7

a) What is the appropriate test statistic?
---Select--- na z-test One-Sample t-test Independent-Samples t-test Related-Samples t-test

b)
Population:
---Select--- students not using grammar-checker grammar-checker students at local university number of errors hand-written test
Sample:
---Select--- students not using grammar-checker grammar-checker students at local university number of errors hand-written test

c) Compute the appropriate test statistic(s) to make a decision about H₀.
(Hint: Make sure to write down the null and alternative hypotheses to help solve the problem.)
p-value =  ; Decision:  ---Select--- Reject H0 Fail to reject H0

d) Using the SPSS results, compute the corresponding effect size(s) and indicate magnitude(s).
If not appropriate, input and/or select "na" below.
d =  ;   ---Select--- na trivial effect small effect medium effect large effect
r² =  ;   ---Select--- na trivial effect small effect medium effect large effect

e) Make an interpretation based on the results.

Those that do not use a grammar-checker make more grammatical errors than students at the university.Those that do not use a grammar-checker make less grammatical errors than students at the university.    Those that do not use a grammar-checker do not make significantly different amount of errors than students at the university.

Answer 1

a) Here, we do not have the population standard deviation given.But we are to test :

Ho:Average number of errors per page in a local university is 7.

vs

H1:Average number of errors per page in a local university is more than 7.

Hence, One sample t test is used. The appropriate test statistic is:

One sample t test.

b)

Population :

Students at local university.

Sample:

Students not using grammar-checker

c)

Note :- Avuge numbir f a docal univrs ity in deneteal Thenj Ho: M-7 vs H:M Lut xi istudut eor in the samels Sample = 8.6835 mun S= Samper sd =59821 s fatishic n=1635anpe $2.15 Tert ie. ebservel fest Statiste 8·4975-구 M398214272 VIG

Ne rjcet Ho at Jwel x 0-01 iff for ivn sampler too:15 Tert Stat 2.6025. Ho at ofzo- 01 ase ThPvalue= - 42 324' o.000334. Dea'sion:- Rej'ect He
d) Need SPSS output. Please provide that for the further computations.