STATS - Can somebody help me out with a question & check an answers?

Hi, I could really use a little help on some of these, and if you dont mind checking some of my answers, I'd appreciate! I am interested in how to work this out, my notes are unclear, so is the book. Thank you!!





1.) A recent survey in Michigan revealed that 60% of the vehicles traveling on highways, where speed limits are posted at 70 miles per hour, were exceeding the limit. Suppose you randomly record the speeds of ten vehicles traveling on US 131 where the speed limit is 70 miles per hour. Let X denote the number of vehicles that were exceeding the limit. Find the expected number of vehicles that are traveling on Michigan highways and exceeding the speed limit.





2.) Which of the following is not true with respect to the binomial setting for n = 6 and p = 0.3?


*a. mean = 1.8*


b. distribution is not symmetrical


c. highest prob. occurs for x = 2


d. std. dev. = 1.26





Thank you

STATS - Can somebody help me out with a question %26amp; check an answers?
1. 6





The expected value of X, a binomial random variable:





E(X) = np = 10(0.60) = 6





2. d


The variance = 1.26. The standard deviation is 1.122.





SD(X) = sqrt(np(1-p)) = sqrt(6(0.3)(0.7)) = 1.122








a, b and c are all true.