A random sample of 100 people from City A has an average IQ of 120 with a SD of 18. Independently of this, a random sample of 150 people from City B has an average IQ of 116 with a SD of 15. Are residents of City A smarter on average? Make a z-test of the difference in average lQs; the null hypothesis is that there is no difference. Round your values to three decimal places.
If the null is right, the expected value of the difference between average IQs in each sample is and the standard error of this difference is estimated to be
The observed difference is
The test statistic is
The P-value is approximately

Kevin has a spinner that has 10 equal sections and 2 sections of each color—red, blue, green, yellow, and purple. kevin spins the spinner 180 times. kevin determines about how many times the spinner will land on red or green, and his work is shown below. -kevin has the formula reversed; it should be the total number of sections over the number of red or green sections. -kevin should have used a 4 in the numerator because there are 2 red sections and 2 green sections. -kevin should multiply by the number of sections in the spinner rather than the total number of spins. -kevin calculated the prediction correctly and did not make any mistakes.