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# More Practice

Want more practice? Type in problems below, or click on the “?” to drill down for example problems.

If you click on the “View Steps” box on the widget’s answer screen, you will go to the **Mathway** site, where you can register for a free seven-day trial of the **full version** (steps included) of the software. You can even get math worksheets.

You can also go directly to the **Mathway** site, where you can register for the trial, or just use the software for free without the detailed solutions. There is even a Mathway App for your mobile device. Enjoy!

Can you please help me with this question

A sample of 40 sales receipts from a grocery store has x = $137 and s = $30.2. Assist the

owner of the grocery store to these values to test, at the 5% level of significance, whether

or not the mean sales at the grocery store is different from $150.

(a) State the null and alternative hypotheses for the test.

(b) Calculate the test statistics.

(c) Determine the rejection region(s) for the test.

(d) State the conclusion for the test giving reasons for your answer.

This is Statistics, which I have not covered yet. Do you mind going to http://www.statisticshowto.com and asking the question there? Sorry about that, Lisa

I created a two documents that may help you. They are on my website: http://www.PaulkUSA.com Click the “Math Support” tab at the top. Then click on “Math Documents” then look for the STATISTICS section. There are two documents at the end of the STATISTICS section.

One document uses the Z statistic and rejection region. The other file uses the t statistic and P-Value comparison. Both approaches reach the same conclusion: Reject the null hypothesis and accept the alternative hypothesis. Therefore, the true mean of grocery store receipts is different from $150 (either more or less).

Do you have more challenging questions for the algebra and trigonometry section? just asking.

Thanks for writing! I know the questions in Mathway aren’t too challenging, but I’d suggest just covering up the answers for my examples (like in the tables) and try them on your own. Would that help? Sorry I don’t have a better answer – this is something I’d like to add in the future (more advanced problems). Lisa

Hi Lisa !

I am trying to solve this question to prepare for the GRE and I can’t figure out which step in my method is incorrect. I have a problem that says Helpers are needed and each helper can make either 2 large cakes per hour or 35 small cakes per hour. The kitchen is available for 3 hours and 20 large cakes and 700 small cakes are needed how many helpers are required. Through the use of proportions I was able to determine that it would take 10 helpers/ hour to make the large cakes and 20 helpers/hour to make the small cakes for a total of 30 helpers/hour. When I try to find how many helpers it would take given 3 hours, I cannot systematically solve for the correct answer which is 10 helpers. I am getting 30 helpers/hour *(3 hours)= 900 helpers which doesn’t make any sense because that is too many people given you have more time to make the cakes. I am not seeing how to set it up to get 10 helpers from the beginning. Can you please help me with this and tell me where I am going wrong? I would really appreciate some advice for this one.

Here’s how I’d do this: Since 20 large cakes are needed, we would need 10 hours (2 large cakes per hour). Since 700 small cakes are needed, we would need additional 20 hours (35 small cakes per hour). So we’ll need

30 hours total. Since 3 hours are available, we would need 10 helpers. Does that make sense? Lisa