A retail store manager knows the average weekly sales revenue for last year was $42 000. The store manager also knows that weekly sales are subject to many factors and show a large amount of variability. The standard deviation for all weekly sales recorded last year was $7500. The manager wants to determine whether the variance in weekly sales has changed during the course of the current year. A random sample of 15 weekly sales figures (in dollars) is selected for the current year and is shown in the table. Assuming that weekly sales are normally distributed, use the data and ? = 0.05 to determine whether the variance in weekly sales has changed.

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28 000 41 000 49 000 32 000 43 000 52 000 33 000 44 000 53 000 24000 37 000 46 000 39 000 48 000