Answer:
(a-1) 22 rookies receiving a rating of 4 or better.
(a-2) 14 rookies received a rating of 2 or worse.
(b-1) Constructed below in explanation.
(b-2) 8% of total rookies received a rating of 5.
Step-by-step explanation:
We are provided the rating of Fifty pro-football rookies on a scale of 1 to 5 based on performance at a training camp as well as on past performance.
The frequency distribution constructed is given below:
  Rating          Frequency 
      1                       4
      2                     10       where ranking of 1 indicate a poor prospect whereas
      3                     14         ranking of 5 indicate an excellent prospect. 
      4                     18
      5                      4
(a-1) Rookies receiving a rating of 4 or better = Rating of 4 + Rating of 5
        So, by seeing the frequency distribution 18 rookies received a rating of 
          4 and 4 rookies received a rating of 5.
Hence, Rookies receiving a rating of 4 or better = 18 + 4 = 22 rookies.
(a-2) Number of rookies received a rating of 2 or worse = Rating of 2 +
                                                                                                  Rating of 1
      So, by seeing the frequency distribution 10 rookies received a rating of 
       2 and 4 rookies received a rating of 1.
Hence, Rookies receiving a rating of 2 or worse = 10 + 4 = 14 rookies.
(b-1) Relative Frequency is calculated as = Each frequency value / 
                                                                          Total Frequency
    Rating        Frequency(f)        Relative Frequency 
      1                       4                          4 / 50 = 0.08
      2                     10                         10 / 50 = 0.2
      3                     14                          14 / 50 = 0.28
      4                     18                          18 / 50 = 0.36
      5                   <u>   4    </u>                       4 / 50  = 0.08
                       <u>= 50 </u>
<u>= 50 </u>                
Hence, this is the required relative frequency distribution.
(b-2) To calculate what percent received a rating of 5 is given by equation :
             <em>  x% of 50 = 4 </em> {Here 4 because 4 rookies received rating of 5}
          x =  = 8% .
 = 8% .
Therefore, 8% of total rookies received a rating of 5.