Performing a study on the development of body height, a student randomly measures the height of 30 persons in country a. the results turn out to be: {1.7, 1.6, 1.8, 1.9, 1.75, 1.83, 1.82, 1.65, 1.95, 1.69, 1.82, 1.87, 1.65, 1.54, 1.98, 1.78, 1.69, 1.75, 1.62, 1.64, 1.75, 1.8, 1.65, 1.7, 1.82, 1.62, 1.83, 1.75, 1.7, 1.65}. in the literature, a result is found that 10 years before, the average height of persons in country a was determined to be 1.73 and standard deviation is 0.2 .given that the acceptable threshold for significance is 5%, can this data be used to show that the average height of individuals in country a has increased in the last 10 years? (show your calculations).

Scarlet bought three pairs of sunglasses and two shirts for $81 and paula bought one pair of sunglasses and five shirts for $105 what is the cost of one pair of sunglasses and one shirt?

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.

What is always true when two whole numbers are subtracted?