A professor using an open source introductory statistics book predicts that 10% of the students will purchase a hard copy of the book, 55% will print it out from the web, and 35% will read it online. At the end of the semester he asks his students to complete a survey where they indicate what format of the book they used. Of the 200 students, 25 said they bought a hard copy of the book, 85 said they printed it out from the web, and 90 said they read it online. (a) State the hypotheses for testing if the professor

The professor was not accurate with his hypothesis.

Null hypothesis: P1 = 12.5%, P2 = 42.5%, P3 = 45%

The alternate hypothesis: At least one proportion of the student will differ from the others.

Step-by-step explanation: To check if the professors hypothesis were inaccurate.

What percentage of student bought a hard copy of the book.

(25 ÷ 200) × 100 = 12.5%

What percentage of the student printed it from the web.

(85 ÷ 200) × 100 = 42.5%

What percentage of the students read it online.

(90 ÷ 200) × 100 = 45%

This means that the professor was not accurate with his hypothesis. Because the proportion of student in his hypothesis was not the same in the actual.

Therefore; the null hypothesis are

P1 = 12.5%, P2 = 42.5%, P3 = 45%

The alternative hypothesis will state that at least one of the proportion will be different from the others.

the value of v.w= -12.

step-by-step explanation:

we are given three vector r,v and w as:

r = < 5, -5, -2> ; v = < 2, -8, -8> ; w = < -2, 6, -5>

we know that r,v and w could also be represented as:

r=5i-5j-2k

v=2i-8j-8k

and w= -2i+6j-5k

where i,j and k are the unit vectors of x,y and z-axis respectively.

also we know that it has the following property:

i.i=1 ; j.j=1; k.k=1

and i.=j.i=i.k=k.i=j.k=k.j=0

i.e. when we multiply two vectors or we find it's dot product we need to only multiply the components of x coordinates with each other; y with each other and z with each other.

hence, v.w= (2i-8j- -2i+6j-5k)

                  = 2×(-2)+(-8)×(6)+(-8)×(-5)

                  = -4-48+40

                  = -12

hence, v.w= -12

if you need , reply with more info. u.