(1) In an investigation of toxins produced by molds that infect corn crops, a biochemist prepares extracts of the mold culture with organic solvents and then measures the amount of the toxic substance per gram of solution. From 6 preparations of the mold culture, the following measurements of the toxic substance (in milligrams) are obtained:1.4, 1.5, 1.8, 1.9, 2.5, 2.2Find a 99% confidence interval for the mean weight (in milligrams) of toxic substance per gram of mold culture in the sampled population.(2) Which of the following statements is true regarding part (a)?(A) The population mean must be inside the confidence interval. (B) The population does not need to be normal. (C) The population must be normal. (D) The population standard deviation ? must be known. (E) The population must follow a t-distribution.

Following arew the solution to this question:

Step-by-step explanation:

Build the 99% trust period of harmful chemicals for both the community, because no information is provided mostly on population standard, they just use t-test procedure to find the necessary trust period.  

The confidence interval of 99 percent for both the mean community is provided by,  

Use Minitab as seen below to get the necessary result:  

T study one: weight  

Variable  N   Mean    stDev  SE Mean  99% CI

weight    6    1.883  0.417   0.170   (1.197, 2.569)

The overall population weight of a toxic material in the above output is 99 percent (1.197, 2.569).

They may say of the 99% trust interval, the 99% trust between about 1.197 mg and 2.569 mg will lie throughout the average population.  

Therefore, the option (A) is valid  

One of conditions would be that the overall population should be standard in attempt to discover the standard deviation. This is the true option (C).

i dont know sorry

step-by-step explanation:

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18