You are helping a bank test whether the mean customer account balance is still the same three months after a new marketing campaign went into effect. Prior to the marketing campaign, the expected mean account balance was $275.

You've taken a random sample of 100 customer accounts. The data appears to the right and is sorted from smallest to largest account balance.

Based on this data, is the average account balance still $275?

Use = .05.

TEST STATISTIC

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Zcalc =X - u

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s/square root of n

Why is this the appropriate test statistic for this scenario?

Is this a one or two tailed hypothesis test?

State the null and alternative hypothesis here.

With an a=.05 would you reject or fail to reject the null hypothesis?