The US Agency for Healthcare Research and Quality (www. ahrq. gov) reported that in 2010 the mean cost of a stay in a hospital for American women aged 18-44 was $15,200. A random sample of 400 hospital stays for American women aged 18-44 showed a mean cost of $16,000, with a standard deviation of $5000. Test whether the population mean cost for a hospital stay for American women aged 18-44 has increased since 2010, using the 5% level of significance.

We conclude that the population mean cost for a hospital stay for American women aged 18-44 has increased since 2010.

Step-by-step explanation:

We are given that the US Agency for Healthcare Research and Quality reported that in 2010 the mean cost of a stay in a hospital for American women aged 18-44 was $15,200.

A random sample of 400 hospital stays for American women aged 18-44 showed a mean cost of $16,000, with a standard deviation of $5000.

Let = population mean cost for a hospital stay for American women aged 18-44.

SO, Null Hypothesis, : $15,200   {means that the population mean cost for a hospital stay for American women aged 18-44 has reduced or remains same since 2010}

Alternate Hypothesis, : > $15,200   {means that the population mean cost for a hospital stay for American women aged 18-44 has increased since 2010}

The test statistics that will be used here is One-sample t test statistics as we don't know about the population standard deviation;

                         T.S.  =  ~

where,   = sample mean cost of a stay in a hospital for American women aged 18-44 = $16,000

              s = sample standard deviation = $5,000

              n = sample of hospital stays = 400

So, test statistics  =     ~

                               =  3.20

Now at 5% significance level, the t table gives critical value of 1.645 at 399 degree of freedom for right-tailed test. Since our test statistics is more than the critical value of t as 1.645 < 3.20, so we have sufficient evidence to reject our null hypothesis as it will fall in the rejection region.

Therefore, we conclude that the population mean cost for a hospital stay for American women aged 18-44 has increased since 2010.

introduction, methodology, results, discussion

step-by-step explanation:

an observational study is one which consists of actual observation to record data and then analyse the data.

there are a number of factors that should be analyzed before starting an observational study.

the main four factors are:

i) introduction:   this should be analysed to check whether the purpose of the study is correctly established and the data recorded are appropriate for the study

methodology:   the method of collecting the data, such as whether randomly selected, and whether sample size matches with the population to be studied, whether questions asked are easy to answer by common men, etc.

results: then results such as summary of data with comments should be studied thoroughly

discussion:   the last is the discussion, this can be either by management people or persons who are all interested , etc.

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step-by-step explanation: