# Question: In a study of reaction times to a specific stimulus

In a study of reaction times to a specific stimulus, a psychologist recorded these data (in seconds).

Class limits Frequency

2.1–2.7 .......12

2.8–3.4 .......13

3.5–4.1 .........7

4.2–4.8 .........5

4.9–5.5 .........2

5.6–6.2 .........1

Find the variance and standard deviation.

Class limits Frequency

2.1–2.7 .......12

2.8–3.4 .......13

3.5–4.1 .........7

4.2–4.8 .........5

4.9–5.5 .........2

5.6–6.2 .........1

Find the variance and standard deviation.

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