Heavy children: are children heavier now than they were in the past? the national health and nutrition examination survey (nhanes) taken between 1999 and 2002 reported that the mean weight of six-year-old girls in the united states was 49.3 pounds. another nhanes survey, published in 2008, reported that a sample of 190 six-year-old girls weighed between 2003 and 2006 had an average weight of 46 pounds. assume the population standard deviation is =σ17 pounds. can you conclude that the mean weight of six-year-old girls in 2006 is different from what it was in 2002? use the =α0.10 level of significance and the critical value method.

Step-by-step explanation:

Hello!

You have two surveys that measure the weight of six-year-old girls in the USA,

1) 1999-2002

μ= 49.3 pounds

(I'll take this mean as the population value since it can be considered "historical data" or point of comparison to make the test.)

2)2003-2006

sample n= 190

sample mean x[bar]= 46 pounds

population standard deviation σ= 17 pounds

Assuming that the study variable X" Weight of six-year-old girls between 2003 - 2006" (pound) has a normal distribution.

If you need to test that the children are heavier now (2003-2006) than in the past (1999-2002) the test hypothesis is:

H₀: μ ≤ 49.3

H₁: μ > 49.3

α: 0.10

The statistic is Z= (x[bar]-μ)   ~N(0;1)

                                (δ/√n)

The critical region is one-tailed to the right.

So you'll reject the null hypothesis if the calculated statistic is equal or greater than 1.28.

Z=  46 - 49.3 = -2.67

     17/√190

Since the calculated value -2.67 is less than 1.28 you do not reject the null hypothesis. In other words, the six-year-old girls from 2003-2006 are thinner than the girls from 1999-2002.

I hope it helps!

points are handed out whenever you post answers.

brainliest answers are handed out by the person asking the question, so whether your answer is picked depends entirely on whether the asker bothers to pick

if you're asking about your rank, it depends on having a certain number of points and a certain number of brainliest answers. for example, at the time of this writing, i have 44338 points out of 15000 needed for the next (nearly triple the requirement! ) but i only have 24 out of 50 required brainliest answers. this number decays, meaning after a certain amount of time (i think about a month), the total number of brainliest answers you've earned doesn't count toward this total. (i've been stuck at the same rank for a long

the lesson to learn here is that you shouldn't worry about points or rank. chances are, no matter how good an answer you may provide, your efforts will go mostly unnoticed unless you focus on the newest/most active questions that get posted.