1.A credit card company is interested in the average balance tht is carried by its college aged card holders. They are particularly interested in whether the average balance of the college aged cardholders is significantly different from that of the cardholders who are in their early 20s, who have an average balance of $1385. A sample of 40 college aged card holder accounts reveals an average balance of $1250 and a SD of $350.
If you were to set up a set of hypotheses for this situation, what woiuld the null and alternative be?
2. In the above mentioned question, what is your decision at alpha=0.01. Justify your answer.
Answer: The college aged users arent different since the Z statistic = -2.44.
3. A survey was conducted by careerbuilder.com to see what percent of managers viewed emotional intelligence as important. Their goal was to create a 95% confidence interval with a margin of error of 1.9 percentage points. How many managers should they have sampled?
Answer: 2661
Why?
4. The results from the above survey were reportedd on August 18,2011 and stated that 34% of hiring managers said they are placing greater emphasis on emotional intelligence. The article used 2662 US hiring managers in the survery. Using this information create a 95 % confidence interval for the results.
Answer: 0.322, 0.358
Why?