What process is mostly responsible for the blue appearance of the sky? a) refraction of light by clouds b) scattering of light by air molecules c) refraction of light by water molecules d) obstruction of yellow light by pollutan

An insurance company wants to know if the average speed at which men drive cars is higher than that of women drivers. the company took a random sample of 27 cars driven by men on a highway and found the mean speed to be 72 miles per hour with a standard deviation of 2.2 miles per hour. another sample of 18 cars driven by women on the same highway gave a mean speed of 68 miles per hour with a standard deviation of 2.5 miles per hour. assume that the speeds at which all men and all women drive cars on this highway are both approximately normally distributed with unknown and unequal population standard deviations.

In a vernier instrument the main scale is in 1/2 mm divisions .vernier is made by redividing 19 such divisions into 20 equal parts. calculate the least count of the instrument.

The diagram shows a series of volcanic island and a hot spot determine the direction of movement of the tectonic plate that for the island