Ryan C. answered 08/21/25
Statistics Expert | Advanced Analysis & Research Methods Tutor
Quick context: 51 observations. I used Sturges’ rule to create 7 class intervals so the bins are sensible for this sample size.
1) How I chose the bins (step-by-step)
- Sample size n=51n = 51n=51.
- Sturges’ rule: k=⌈1+3.322log10(n)⌉k = \lceil 1 + 3.322\log_{10}(n)\rceilk=⌈1+3.322log10(n)⌉.
- log10(51)=1.7075701761\log_{10}(51) = 1.7075701761log10(51)=1.7075701761 (calculated).
- 3.322×1.7075701761=5.6725481250.3.322\times 1.7075701761 = 5.6725481250.3.322×1.7075701761=5.6725481250.
- Add 1 → 6.67254812506.67254812506.6725481250.
- Ceiling → 7 bins.
- Class width =max−min7=25.0−4.27=20.87≈2.9714.=\dfrac{\text{max} - \text{min}}{7} = \dfrac{25.0 - 4.2}{7} = \dfrac{20.8}{7} \approx 2.9714.=7max−min=725.0−4.2=720.8≈2.9714.
2) Frequency distribution (7 bins — right-inclusive)
| Class interval (approx)Frequency | |
| 4.179 – 7.171 | 1 |
| 7.171 – 10.143 | 5 |
| 10.143 – 13.114 | 12 |
| 13.114 – 16.086 | 10 |
| 16.086 – 19.057 | 13 |
| 19.057 – 22.029 | 8 |
| 22.029 – 25.000 | 2 |
Check: 1+5+12+10+13+8+2=511+5+12+10+13+8+2 = 511+5+12+10+13+8+2=51 (all data included).
3) Relative frequency distribution (proportion and percent)
| Class intervalRelative frequency (proportion)Percent | ||
| 4.179 – 7.171 | 0.0196 | 1.96% |
| 7.171 – 10.143 | 0.0980 | 9.80% |
| 10.143 – 13.114 | 0.2353 | 23.53% |
| 13.114 – 16.086 | 0.1961 | 19.61% |
| 16.086 – 19.057 | 0.2549 | 25.49% |
| 19.057 – 22.029 | 0.1569 | 15.69% |
| 22.029 – 25.000 | 0.0392 | 3.92% |
Cumulative percent after each bin: 1.96%, 11.76%, 35.29%, 54.90%, 80.39%, 96.08%, 100.00%.
4) ASCII (text) Frequency Histogram — copy/paste friendly
(Each * = 1 observation)
5) ASCII Relative-Frequency “Histogram” (percent)
(Each # ≈ 2.5% — rough visual)
6) Summary statistics (useful for interpretation)
- n = 51
- Min = 4.2, Max = 25.0 (range = 20.8)
- Mean ≈ 15.1765
- Median = 15.5
- Sample standard deviation ≈ 4.40
- Skewness (moment-based) ≈ -0.05 (very close to 0; distribution is approximately symmetric)
7) Plain-language description you can paste directly
The dataset (51 values) ranges from 4.2 to 25.0 and is split into seven equal-width bins. Most values fall in the middle ranges: roughly 59% of the data lie between 10.14 and 19.06 (that’s the three middle bins). The single largest bin is 16.09–19.06 (25.5% of the observations). There’s one small low-value observation near 4.2 and a small handful of higher values near and above 19, but overall the distribution is approximately symmetric and unimodal with its center around 15–16. Typical variability (sample SD) is about 4.4 units.
8) Quick interpretation tips (for students / parents)
- Center: Around 15–16 (median 15.5).
- Spread: Most data lie within about ±4.4 of the mean (so many between ~11 and ~19).
- Outliers: 4.2 is an unusually low observation; 25.0 is a high-value but not extreme relative to the rest.
- Shape: Single peak (unimodal) and roughly symmetric — no strong long tail to one side.
9) If you want to show work / reproduce this
-
Excel:
=FREQUENCY()with bin boundaries (7 bins) or use PivotTable grouping on a numeric column. -
Google Sheets: same
FREQUENCY()+ chart → Histogram. - Calculator/hand: use Sturges’ rule to pick number of classes (I showed steps), compute class width, then tally counts per class.