3. Number of Credit Cards A bank vice president feels that each savings account customer has, on average,
three credit cards. The following distribution represents
the number of credit cards people own. Find the mean,
variance, and standard deviation. Is the Vice President
correct?
Number of
card
X
5 6 7 8 9 10
P(x) 0.05 0.2 0.4 0.1 0.15 0.1

Ijust need these 2 questions answered (the second pic is just confirmation i'm not confident in that answer)

Use sigma notation to represent the following series for 9 terms.

Aprofessional hockey team has noticed that, over the past several seasons, as the number of wins increases, the total number of hot dogs sold at the concession stands increases. the hockey team concludes that winning makes people crave hot dogs. what is wrong with the hockey team's conclusion? a) it does not take into account the attendance during each season. b) it does not take into account the number of hamburgers sold during each season. c) it does not take into account the number of concession stands in the hockey arena. d) it does not take into account the number of seasons the hockey team has been in existence.