The score on a proficiency measure is assumed to follow a normal distribution. A switch to...

The score on a proficiency measure is assumed to follow a normal distribution. A switch to better lighting might change the score. A random sample of 30 people taken during the year before the switch to better light yielded a mean score of 600 and a variance of 400. A different random sample of 30 people after the switch had a mean of 610 and a variance of 441. Important: use a degrees of freedom nu=80 for the t statistic. Does the change in lighting seem to have changed the proficiency score? Show your calculations (but not the degrees of freedom formula) and explain using one or two sentences.

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orchestra answered 1 year ago

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