Statistics Questions & Answers

b. Compute Cohen's \( d \) to measure the size of the effect IF it exists.

QUESTION 1 The data below shows the number of laptops sold by 15 sales agents during the last financial year. \( \begin{array}{lllllllllllllll}43 & 48 & 62 & 52 & 46 & 90 & 58 & 37 & 48 & 73 & 84 & 68 & 54 & 34 & 78 \\ 1.1 & \text { Determine the median of the number of laptops sold. } \\ 1.2 & \text { Calculate the range of the data. }\end{array} \) 1.3

\( \begin{array}{llllllllllllllll}43 & 48 & 62 & 52 & 46 & 90 & 58 & 37 & 48 & 73 & 84 & 68 & 54 & 34 & 78 & \\ 1.1 & \text { Deteruine the median of the number of laprops sold. } & & & & & & \\ 1.2 & \text { Calculate the range of the data. }\end{array} \)

women without tattoo \( \mu=4.9 \) women with a taitoo Sample \( n=16 \) Indicate a significant differences. Use a two tailed test with \( a=0.05 \)

and culate \( p \) ualue ins if sample is 16 and \( t \) stat is -0.83 .

18. There is evidence indicating that people with visible tattoos are viewed more negatively than people without visible tattoos. On a 7-point scale, people rated a woman without a tattoo with an average rating of \( \mu=4.9 \), the standard deviation of these scores was \( \sigma=0.84 \). The researcher modified the picture of the woman so she now had a tattoo of Groot on her left arm. This was shown to a sample of \( \mathrm{n}=16 \) students and the students used the same 7 -point scale to rate the attractiveness of the woman. The average score for the photo with the tattoo was \( M=4.2 \). (8 points) a. Do the data indicate a significant difference in rated attractiveness when the woman appeared to have a tattoo? Use a two-tailed

1. Las edades de 8 profesoras de primaria son: \( \begin{array}{llllll}30 & 40 & 35 & 40 & 38 & 35\end{array} 45 \quad 37 \) ¿Cuál es el promedio de edad de las profesoras de primaria?

7 A mechanical component fails, on average, 3 times out of every 10 . An engineer designs a new system of manufacture that he believes reduces the likelihood of failure. He tests a sample of 20 components made using his new system. a Describe the test statistic. b State suitable null and alternative hypotheses. c Using a \( 5 \% \) level of significance, find the critical region for a test to check his belief, ( 2 marks), ( 3 marks) d Write down the actual significance level of the test.

17. Define the alpha level and the critical region and explain how they are related. (4 points)

16. The scores on a standardized math test for 8th grade children form a normal distribution with a mean of 70 and a standard deviation of 10. (8 points) a. What proportion of the students have scores less than \( X=73 \) ? b. If samples of \( n=6 \) are selected from the population, what proportion of the samples have means less than \( M=73 \) ? c. If samples of \( n=30 \) are selected from the population, what proportion of the samples will have means less than \( M=73 \) ?