4. SpaceX decided to send 10 male rats into space. Upon their return, the red blood cell mass (in millilitres) of the rats was determined. A control group of 10 male rats was held under the same conditions (except for space flight) as the space rats, and their red blood cell mass was also determined when the space rats returned. SpaceX wants to determine if there is a difference in red blood cell mass between the two groups after space flight. An Excel output of the comparison of the groups at the 1% level of significance is below. [6] t-Test: Two-Sample Assuming Equal Variances Flight Control Mean 8.044 3.158 Variance 0.930738 0.966929 Observations 10 10 Pooled Variance 0.948833 Hypothesized Mean 0 df 18 t Stat 0.26169 P(T