The mean annual premium for automobile insurance in the united states is $1503 (insure website, march 6, 2014). being from pennsylvania, you believe automobile insurance is cheaper there and wish to develop statistical support for your opinion. a sample of 25 automobile insurance policies from the state of pennsylvania showed a mean annual premium of $1440 with a standard deviation of s = $165. if required, enter negative values as negative numbers.
a. develop a hypothesis test that can be used to determine whether the mean annual premium in pennsylvania is lower than the national mean annual premium.

Identify the type of observational study described. a statistical analyst obtains data about ankle injuries by examining a hospital's records from the past 3 years. cross-sectional retrospective prospective

Martha has a deck of cards. she has lost some of the cards, and now the deck only contains nine spades, eleven diamonds, eight clubs, and twelve hearts. martha predicts that whenever she draws a card from the deck without looking, she will draw a club one-fifth of the time. which activity would best allow martha to test her prediction? a. randomly draw a card from the box and see if it is a club. b. randomly draw a card. then, continue to draw another card until all eight clubs are drawn. c. randomly draw and replace a card 120 times. then, observe how close to 30 times a club is drawn. d. randomly draw and replace a card 100 times. then, observe how close to 20 times a club is drawn.

X/y + 4y/x divided by x/y - 2y/x explain as in depth as you can how you simplfied the fractions. i don't know where to start on this : /