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Statistics: Mean and Mode Calculations

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Questions and Answers

What is the arithmetic mean of the dataset 20, 38, 56, 12, 76?

30.2

45.6

50.8

40.4 (correct)

The mean calculated from the frequencies for the dataset provided is approximately 12.095.

True

What is the sum of the frequencies (n) from the frequency distribution for class intervals?

The mean for the class interval data is _____ when dividing the sum of fx (435) by the sum of frequencies (19).

22.895 Signup and view all the answers

Match the following datasets with their corresponding means:

Dataset A (20, 38, 56, 12, 76) = 40.4 Dataset B (x, f from table) = 12.095 Dataset C (class intervals) = 22.895 Signup and view all the answers

What is the mode of the dataset: 20, 38, 56, 12, 76, 76, 21, 76?

76 Signup and view all the answers

The mode of a frequency distribution is the value that appears the least number of times.

False Signup and view all the answers

What class interval has the highest frequency in the grouped frequency distribution table provided?

20-30 Signup and view all the answers

In the calculation of the mode, $L_1$ represents the ______ class limit of the modal class.

lower Signup and view all the answers

Match the following data types with their corresponding modes:

Raw Data = 76 Frequency Distribution Table = 13 Grouped Frequency Distribution Table = 20-30 Signup and view all the answers

What is the formula for calculating the coefficient of correlation r?

$r = (ΣXY - (ΣX * ΣY) / n) / √[ (ΣX² - (ΣX)² / n) * (ΣY² - (ΣY)² / n)] Signup and view all the answers

The coefficient of correlation calculated in the problem is 0.918.

False Signup and view all the answers

What is the value of ΣXY given in the data?

3050 Signup and view all the answers

The sum of the values of X is represented as ΣX, and its value is _____

179 Signup and view all the answers

Match the variables with their corresponding values:

ΣX = 179 ΣY = 77 ΣXY = 3050 ΣX² = 7697 Signup and view all the answers

Study Notes

Arithmetic Mean Calculations

The arithmetic mean is calculated by summing all the values and dividing by the number of values.
In the first example, the sum of the values is 202 and there are 5 values.
The mean in this case is 40.4.
The second example demonstrates how to calculate the mean of a dataset with frequencies.
The mean is calculated as the sum of the products of each value and its frequency, divided by the total number of values.
The third example shows how to calculate the mean of a grouped frequency distribution.
Each class interval has its own midpoint and frequency. The sum of the products of each midpoint and its frequency is divided by the total number of values to get the mean.

Finding the Mode

The mode is the value that appears most frequently in a dataset.
In a frequency distribution, the mode is the value with the highest frequency.
In a grouped frequency distribution, the modal class is the class interval with the highest frequency.
The mode is calculated using a formula: Mode = $L_1 + \frac{(f_1 - f_0)}{2f_1 - f_0 - f_2} \times h$
The formula uses the lower limit of the modal class, the frequencies of the modal and surrounding classes, and the class interval width.

Coefficient of Correlation Calculation

The coefficient of correlation (r) measures the strength and direction of the linear relationship between two variables.
The formula used is: r = (ΣXY - (ΣX * ΣY) / n) / √[ (ΣX² - (ΣX)² / n) * (ΣY² - (ΣY)² / n)]
In the calculation, ΣX represents the sum of all X values, ΣY represents the sum of all Y values, ΣXY represents the sum of all X*Y values, ΣX² represents the sum of all X² values, and ΣY² represents the sum of all Y² values.
'n' refers to the total number of data points.
The final result of the correlation calculation is -2.67.
This indicates a negative correlation, suggesting that as one variable increases, the other tends to decrease. However, it's important to remember that this is an imperfect correlation and needs to be interpreted with caution.

Conclusion

The notes provide a basic understanding of how to calculate the arithmetic mean, mode, and coefficient of correlation for different datasets.
The notes also provide example calculations for each measure.

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Description

This quiz covers the calculations of the arithmetic mean and mode in various data distributions. You'll learn how to compute the mean for simple datasets, datasets with frequencies, and grouped frequency distributions. Additionally, the quiz explains how to identify the mode in both frequency and grouped frequency distributions.