There are a total of 297 students in the 7th grade. Rough estimates would say that about half of that number are boys and half are girls. Asking only 50 random girls would be biased because not only would it not be all of the girls (the number of girls would be around 148 or 149) but it would also be ignoring the roughly 148 to 149 boys there are on estimate. The sample would be biased because it would be ignoring the opinions of more than half the seventh grade.
Answer:
I subtracted the highest and lowest numbers. The range for new cars was 31. The range for old cars was 75. The range for used cars was much bigger.
Hope's this helps you.
50% of X-Treamline Crank Radios are likely to play 30 minutes or longer after 30 cranks, while only 25% of Secure Hike Emergency Radios are likely to play 30 minutes or longer after 30 cranks