Missing Exam Grade A professor has recorded exam grades for 20 students in his class, but one of the grades is no longer readable. If the mean score on the exam was 82 and the mean of the 19 readable scores is 84, what is the value of the unreadable score?
Table of contents
- 1. Intro to Stats and Collecting Data1h 14m
- 2. Describing Data with Tables and Graphs1h 55m
- 3. Describing Data Numerically2h 5m
- 4. Probability2h 16m
- 5. Binomial Distribution & Discrete Random Variables3h 6m
- 6. Normal Distribution and Continuous Random Variables2h 11m
- 7. Sampling Distributions & Confidence Intervals: Mean3h 23m
- Sampling Distribution of the Sample Mean and Central Limit Theorem19m
- Distribution of Sample Mean - Excel23m
- Introduction to Confidence Intervals15m
- Confidence Intervals for Population Mean1h 18m
- Determining the Minimum Sample Size Required12m
- Finding Probabilities and T Critical Values - Excel28m
- Confidence Intervals for Population Means - Excel25m
- 8. Sampling Distributions & Confidence Intervals: Proportion1h 25m
- 9. Hypothesis Testing for One Sample3h 29m
- 10. Hypothesis Testing for Two Samples4h 50m
- Two Proportions1h 13m
- Two Proportions Hypothesis Test - Excel28m
- Two Means - Unknown, Unequal Variance1h 3m
- Two Means - Unknown Variances Hypothesis Test - Excel12m
- Two Means - Unknown, Equal Variance15m
- Two Means - Unknown, Equal Variances Hypothesis Test - Excel9m
- Two Means - Known Variance12m
- Two Means - Sigma Known Hypothesis Test - Excel21m
- Two Means - Matched Pairs (Dependent Samples)42m
- Matched Pairs Hypothesis Test - Excel12m
- 11. Correlation1h 24m
- 12. Regression1h 50m
- 13. Chi-Square Tests & Goodness of Fit2h 21m
- 14. ANOVA1h 57m
3. Describing Data Numerically
Mean
Problem 3.RE.7
Textbook Question
Weighted Mean Michael has just completed his first semester in college. He earned an A in his five-hour calculus course, a B in his four-hour chemistry course, an A in his three-hour speech course, and a C in his three-hour psychology course. Assuming an A equals 4 points, a B equals 3 points, and a C equals 2 points, determine Michael’s grade-point average if grades are weighted by class hours.
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Identify the grade points for each course based on the given scale: A = 4 points, B = 3 points, and C = 2 points.
List the credit hours and corresponding grade points for each course: Calculus (5 hours, 4 points), Chemistry (4 hours, 3 points), Speech (3 hours, 4 points), Psychology (3 hours, 2 points).
Calculate the weighted grade points for each course by multiplying the grade points by the credit hours: for example, weighted points for Calculus = 5 \times 4.
Sum all the weighted grade points from each course to get the total weighted points.
Sum all the credit hours to get the total number of hours, then divide the total weighted points by the total credit hours to find the weighted mean (GPA): \(\text{GPA} = \frac{\sum (\text{grade points} \times \text{credit hours})}{\sum \text{credit hours}}\).
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Weighted Mean
The weighted mean is an average where each value contributes proportionally based on its assigned weight. In this context, grades are weighted by the number of credit hours for each course, reflecting their relative importance in calculating the overall GPA.
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Calculating the Mean
Grade Point Conversion
Grades are converted into numerical values (e.g., A=4, B=3, C=2) to quantify academic performance. This conversion allows for mathematical operations like averaging to determine a student's GPA.
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Grade Point Average (GPA) Calculation
GPA is calculated by multiplying each course's grade point by its credit hours, summing these products, and dividing by the total credit hours. This weighted average reflects the student's overall academic performance.
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