Q3: The table shows the distribution of scores or 40 students on a Math test. (a) Estimate the mean score obtained on the test. (b) Estimate the probability that a student selected at random would score at most 15 marks on the test. (10 marks) Score 10 - 12 13 - 15 16 - 18 19 - 21 22 - 24 Frequency 4 6 13 9 8
Added by Felix B.
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The midpoints are: - 11 for the interval 10-12 - 14 for the interval 13-15 - 17 for the interval 16-18 - 20 for the interval 19-21 - 23 for the interval 22-24 Now, let's find the product of the midpoints and their corresponding frequencies: - 11 * 13 = 143 - 14 * Show more…
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A teacher predicts that the distribution of grades on the final exam will be and they are recorded in Table 11.27. $$\begin{array}{|l|l|}\hline \text { Grade } & {\text { Proportion }} \\ \hline A & {0.25} \\ \hline B & {0.30} \\ \hline C & {0.35} \\ \hline D & {0.10} \\ \hline\end{array}$$ The actual distribution for a class of 20 is in Table 11.28. $$\begin{array}{|l|l|}\hline \text { Grade } & {\text { Frequency }} \\ \hline A & {7} \\ \hline B & {7} \\ \hline B & {7} \\ \hline C & {5} \\ \hline D & {1} \\ \hline\end{array}$$ $\chi^{2}$ test statistic $=$________
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A sample of test scores is normally distributed with a mean equal to 20 and a variance equal to 25. a) what percentage of scores is between 15 and 25? b) what raw score is the cutoff for the top 10% of scores? c) what is the probability of a score less than 27? d) what is the proportion below 13? Please show all work and steps.
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