Statistics Chapter on Sampling and Data Measures

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Questions and Answers

What is the main distinction between Simple Random Sampling and Stratified Random Sampling?

Simple Random Sampling selects individuals from the entire population randomly. (correct)
Stratified Random Sampling divides the population into subgroups before sampling. (correct)
Simple Random Sampling guarantees equal representation from all subgroups.
Stratified Random Sampling collects data only from strata that are overrepresented.

Calculate the median from the following set of numbers: 88.03, 94.50, 94.90, 95.05, 84.60.

94.90 (correct)
88.03
94.50
95.05

What is the mode of the following data set: 185-195: 2, 195-205: 1, 205-215: 3, 215-225: 4, 225-235: 5, 235-245: 6, 245-255: 4, 255-265: 3, 265-275: 2, 275-245: 1?

215-225
235-245 (correct)
225-235
195-205

How would you calculate the mean of the following grouped data: 185-195 (2), 195-205 (1), 205-215 (3), 215-225 (4), 225-235 (5), 235-245 (6), 245-255 (4), 255-265 (3), 265-275 (2), 275-245 (1)?

<p>By averaging the midpoints of each range weighted by their frequencies. (C)</p> Signup and view all the answers

What is the standard deviation of the data represented in ranges: 185-195 (2), 195-205 (1), 205-215 (3), 215-225 (4), 225-235 (5), 235-245 (6), 245-255 (4), 255-265 (3), 265-275 (2), 275-245 (1)?

<p>It is determined using the variance of each range. (C)</p> Signup and view all the answers

Flashcards

Simple Random Sampling vs. Stratified Random Sampling

In simple random sampling, each individual in the population has an equal chance of being selected. Stratified random sampling divides the population into subgroups (strata) based on shared characteristics and then randomly samples from each stratum.

Mean, Median, Mode

The mean is the average of a dataset. The median is the middle value when the dataset is ordered. The mode is the most frequent value in the dataset.

Calculating Mean, Median & Mode

The mean is calculated by summing all values and dividing by the number of values. The median is the middle value when the dataset is ordered. The mode is the value that occurs most frequently.

Mean, Median, Mode for Grouped Data

The mean is calculated by summing all values and dividing by the number of values. The median is the middle value when the dataset is ordered (using the midpoint for grouped data). For the mode, identify the group with the highest frequency.

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Standard Deviation

The standard deviation measures the spread or dispersion of data points around the mean. A higher standard deviation indicates greater variability in the data.

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Study Notes

Q1: Difference Between Sampling Methods

Simple Random Sampling and Stratified Random Sampling differ in how they select samples from a population.
Simple Random Sampling involves selecting individuals purely at random, while Stratified Random Sampling divides the population into groups (strata) and then randomly selects individuals from each group.