Urgent brainliest given mr brown gives his class a test. the 10 girls in the class get a mean mark of 70%.the 15 boys in the class get a mean mark of 80%.nick says that because the mean of 70 and 80 is 75 then the mean mark for the whole class in the test is 75%. nick is not correct. is the correct mean less than or greater than 75%? you must justify your answer.

Use the quadratic formula to solve the equation. if necessary, round to the nearest hundredth. x^2 - 20 = x a. 5, 4 b. -5, -4 c. -5, 4 d. 5, -4

The fraction of defective integrated circuits produced in a photolithography process is being studied. a random sample of 300 circuits is tested, revealing 17 defectives. (a) calculate a 95% two-sided confidence interval on the fraction of defective circuits produced by this particular tool. round the answers to 4 decimal places. less-than-or-equal-to p less-than-or-equal-to (b) calculate a 95% upper confidence bound on the fraction of defective circuits. round the answer to 4 decimal places. p less-than-or-equal-to

Bring the fraction a/a-4 to a denominator of 16-a^2