I have the answer to this question,, but i'd like to know how to do it. I need help finding z. Any help would be great. Thanks.

Children and McDonald�fs In a Sports Illustrated for Kids survey of 603 children, 43%
preferred McDonald�fs for fast food. The next highest rating went to Taco Bell, preferred by
13% of the children. An advertising executive claims that McDonald�fs is preferred by less than
half of all children. Test that claim using a 0.05 significance level.

I think I use the following formula:

z = p-hat - p / �ã pq/n

You are correct, to test the claim using a 0.05 significance level, you can utilize the formula for the z-test. Let's break down the formula you mentioned:

1. p-hat: This represents the sample proportion. In this case, it is the proportion of children who prefer McDonald's, which is given as 43% or 0.43.

2. p: This represents the claimed proportion. The advertising executive claims that McDonald's is preferred by less than half of all children, so we would use a value less than 0.5.

3. q: This is the complement of p and represents the proportion of children who do not prefer McDonald's. In this case, q = 1 - p or 1 - 0.43 = 0.57.

4. n: This represents the sample size, which is given as 603 in the survey.

The formula for z is:

z = (p-hat - p) / (√(p * q / n))

Now let's compute the value of z and determine if the claim can be rejected.

z = (0.43 - p) / (√(0.43 * 0.57 / 603))

To determine if the claim can be rejected, we need to compare the absolute value of z to a critical z-value at a significance level of 0.05. The critical z-value is usually obtained from a z-table or calculated using statistical software. For a 0.05 significance level, the critical z-value is approximately ±1.96.

If the absolute value of z is greater than 1.96, then we can reject the claim that McDonald's is preferred by less than half of all children.

Remember, p represents the claimed proportion, which in this case should be less than 0.5. You need to substitute a specific value for p in the formula and calculate the z-value to examine the claim using the given data.