Sample Questions of Language Teaching Methodology

Topics: Arithmetic mean, Achievement test, Pearson product-moment correlation coefficient Pages: 5 (799 words) Published: May 16, 2013
Lab Activity 3

ACTIVITY 1
http://math.colgate.edu/math102/dschult/examples/ANOVA/anovanc.html A researcher would like to find out whether a man's nickname affects his cholesterol reading (though it is not clear why she believes it should). She records the cholesterol readings of 23 men nicknamed Sam, 24 men nicknamed Lou and 19 men nicknamed Mac; her data appears in the table to the right. She wants to know whether the differences in the average readings are significant; i.e., whether the average reading of all men nicknamed Sam is different from the average reading of all Lous or whether these averages differ from the average reading of all Macs. |Sam |Lou |Mac |

|364 |260 |156 |
|245 |204 |438 |
|284 |221 |272 |
|172 |285 |345 |
|198 |308 |198 |
|239 |262 |137 |
|259 |196 |166 |
|188 |299 |236 |
|256 |316 |168 |
|263 |216 |269 |
|329 |155 |296 |
|136 |212 |236 |
|272 |201 |275 |
|245 |175 |269 |
|209 |241 |142 |
|298 |233 |184 |
|342 |279 |301 |
|217 |368 |262 |
|358 |413 |258 |
|412 |240 | |
|382 |243 | |
|593 |325 | |
|261 |156 | |
| |280 | |

ACTIVITY 2

http://www.webster.edu/~woolflm/correlation.html
It is assumed that achievement test scores should be correlated with student's classroom performance. One would expect that students who consistently perform well in the classroom (tests, quizes, etc.) would also perform well on a standardized achievement test (0 - 100 with 100 indicating high achievement). A teacher decides to examine this hypothesis. At the end of the academic year, she computes a correlation between the students achievement test scores (she purposefully did not look at this data until after she submitted students grades) and the overall g.p.a. for each student computed over the entire year. The data for her class are provided below.

|Achievement |G.P.A. |
|98 |3.6 |
|96 |2.7 |
|94 |3.1 |
|88 |4.0 |
|91 |3.2 |
|77 |3.0 |
|86 |3.8 |
|71 |2.6 |
|59 |3.0 |
|63 |2.2 |
|84 |1.7 |
|79 |3.1 |
|75 |2.6 |
|72 |2.9 |
|86 |2.4 |
|85 |3.4 |
|71 |2.8 |
|93 |3.7 |
|90 |3.2 |
|62 |1.6 |

1. Compute the correlation coefficient.

2. What does this statistic mean concerning the relationship between achievement test prformance and g.p.a.?

3. What percent of the variability is accounted for by the relationship between the two variables and what does this statistic mean?

4. What would be the slope and y-intercept for a regression line based on this data?

5. If a student scored a 93 on the achievement test, what would be their predicted G.P.A.? If they scored a 74? A 88?

ACTIVITY 3 (from textbook)

A professor in the psychology department would like to determine whether there has been a significant change in grading practices over the years. It is known that the overall grade distribution for the department in 1985 had 14% As, 26% Bs, 31% Cs, 19% Ds and 10% Fs. A sample of n=200 psychology students from last semester produced the following grade distribution:

|A |B |C |D |F | |32 |61 |64...