Is the length of a steel bar affected by the heat treatment technique used? This was the

€œIs the length of a steel bar affected by the heat treatment technique used?€ This was the question being tested when the following data were collected.

a. Find the means and standard deviations for the two sets of data.
b. Find evidence about the sample data (both graphic and numeric) that support the assumption of normality for the two sampled populations.
c. Find the 95% confidence interval for m 1 = m 2.

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Lengths (to the nearest inch) Heat Treatment 1 156 159 15 153 157 159 155 155 15 152 158 154 156 156 157 155 156 159 153 157 157 159 158 155 159 152 150 154 156 156 157 l60 2 154 156 150 15 156 155 153 154 149 150 150 151 154 155 155 154 154 156 150 15T 156 154 153 154 149 150 150 151 154 148 155 158