Equivalent Text: Representativeness, Random Selection & Sample Size

This static document mirrors the app’s behavior (same population and sampling logic) and presents accessible summaries of samples and cumulative results.

Introduction

Purpose. This document is an accessible, text-first companion to the app Is the Sample Representative: Random Selection and Sample Size. It mirrors the app’s logic without graphics so learners using screen readers or preferring text can explore random selection, representativeness, and how sample size affects results.

What you will see for each size.

  1. A Sampling of Ten Samples — Ten independent samples of size n, reporting only the sample mean (x̄) for each sample.
  2. The Central Limit Theorem in Action — Cumulative results showing the Number of Samples and the Mean of Means at checkpoints (1–10 every 1; 20–100 every 10; 200–1000 every 100).

All values are formatted to three decimal places; integer counts use thousands separators.

Size 5

A Sampling of Ten Samples
Mean
24.400
21.000
25.200
24.600
26.200
23.000
19.800
27.800
23.600
21.800

Ten independent samples of size 5; each row reports only the sample mean (x̄). Values are to three decimals.

The Central Limit Theorem in Action
Number of SamplesMean of Means
126.600
227.500
326.867
426.150
526.040
626.033
726.600
825.625
925.778
1025.460
2024.730
3024.347
4024.190
5024.084
6024.210
7024.154
8024.097
9024.044
10024.000
20024.238
30024.177
40024.044
50023.989
60024.010
70023.979
80023.987
90023.998
1,00023.988

Cumulative reporting: after each of the first 10 samples, then every 10 through 100, and every 100 through 1,000.

Size 25

A Sampling of Ten Samples
Mean
24.400
23.480
23.960
24.400
23.120
23.440
23.840
24.840
25.360
23.040

Ten independent samples of size 25; each row reports only the sample mean (x̄). Values are to three decimals.

The Central Limit Theorem in Action
Number of SamplesMean of Means
125.440
224.940
323.440
423.140
523.512
623.913
724.046
824.265
924.267
1024.392
2024.344
3024.377
4024.365
5024.274
6024.317
7024.216
8024.204
9024.209
10024.192
20024.062
30024.098
40024.040
50024.043
60024.041
70024.015
80023.991
90024.001
1,00023.989

Cumulative reporting: after each of the first 10 samples, then every 10 through 100, and every 100 through 1,000.

Size 100

A Sampling of Ten Samples
Mean
23.190
22.560
24.160
23.730
24.300
24.650
22.240
24.800
24.100
23.570

Ten independent samples of size 100; each row reports only the sample mean (x̄). Values are to three decimals.

The Central Limit Theorem in Action
Number of SamplesMean of Means
123.380
223.785
323.837
423.918
523.858
623.845
723.910
824.059
924.028
1023.932
2023.871
3023.864
4023.967
5023.991
6024.051
7024.106
8024.093
9024.079
10024.069
20024.054
30024.032
40024.046
50024.025
60024.025
70024.029
80024.022
90024.009
1,00024.016

Cumulative reporting: after each of the first 10 samples, then every 10 through 100, and every 100 through 1,000.

Size 1000

A Sampling of Ten Samples
Mean
23.682
23.735
23.971
23.936
23.796
23.683
24.001
23.728
24.039
23.629

Ten independent samples of size 1,000; each row reports only the sample mean (x̄). Values are to three decimals.

The Central Limit Theorem in Action
Number of SamplesMean of Means
123.761
223.901
324.021
424.054
524.084
624.027
724.044
824.033
924.030
1023.995
2023.936
3023.952
4023.945
5023.963
6023.995
7023.991
8023.987
9023.994
10023.999
20024.001
30023.999
40024.004
50024.009
60024.005
70024.002
80024.003
90024.000
1,00024.001

Cumulative reporting: after each of the first 10 samples, then every 10 through 100, and every 100 through 1,000.

Methodology for Generating Values

Population. SWLS scores are integers from 5 to 35. We simulate a truncated normal so the truncated population has mean μ = 24 and SD = 6. We solve for parameters (μsim, σsim) of an underlying normal and truncate to [5,35].

Sampling. Each sample of size n is drawn independently with the same truncation and integer rounding used in the app. For each sample we compute only the mean x̄. For the cumulative table we report only the number of samples drawn and the mean of the accumulated sample means.