A company that develops fertilizers wants to know whether either of the two new fertilizers they have in development shows a significant difference in the growth of plants based on a 95% confidence level. The company has data on the growth of bean plants without fertilizers. For a growth period of one month, the population of the beans grown without fertilizers have a mean of 20cm with a standard deviation of 1 cm .
To test fertilizer B, the researcher chooses 35 plants at random. The bean plants' growth averages 20.3 cm . What is the z -score for the mean of the sample treated with fertilizer B compared to the population of bean plants without fertilizer?
