Suppose a certain type of fertilizer has an expected yield per acre of μ1 with variance s2, whereas the expected yield for a second type of fertilizer is m2 with the same variance s2. Let S21 and S22 denote the sample variances of yields based on sample sizes n1 and n2, respectively, of the two fertilizers. Show that the pooled (combined) estimator μ1 with variance σ2, is an unbiased estimator of σ2.

In new york city at the spring equinox there are 12 hours 8 minutes of daylight. the longest and shortest days of the year very by two hours and 53 minutes from the equinox in this year the equinox falls on march 21 in this task you use trigonometric function to model the hours of daylight hours on certain days of the year in new york city a. what is the independent and dependent variables? b. find the amplitude and the period of the function. c. create a trigonometric function that describes the hours of sunlight for each day of the year. d. graph the function you build in part c. e. use the function you build in part c to find out how many fewer daylight hours february 10 will have than march 21. you may look at the calendar.

Prove sin2a + cos2a - 1 / sin2a + cos2a + 1 = 1 - tana / 1 + cota

1. how do you convert the repeating, nonterminating decimal 0. to a fraction? explain the process as you solve the problem.