> q1a <- c(1,0,1,0,0,1)
> q1b <- c(0,0,1,1,1,0)
> q1c <- c(0,0,1,1,1,1)
> df <- data.frame(q1a=q1a,q1b=q1b,q1c=q1c)
> cor(df)
           q1a        q1b       q1c
q1a  1.0000000 -0.3333333 0.0000000
q1b -0.3333333  1.0000000 0.7071068
q1c  0.0000000  0.7071068 1.0000000
> psych::alpha(df)
Some items ( q1a ) were negatively correlated with the total scale and 
probably should be reversed.  
To do this, run the function again with the 'check.keys=TRUE' option
Reliability analysis   
Call: psych::alpha(x = df)

  raw_alpha std.alpha G6(smc) average_r  S/N  ase mean   sd median_r
      0.28       0.3    0.57      0.12 0.43 0.53 0.56 0.34        0

 lower alpha upper     95% confidence boundaries
-0.75 0.28 1.32 

 Reliability if an item is dropped:
    raw_alpha std.alpha G6(smc) average_r  S/N alpha se var.r med.r
q1a      0.83      0.83    0.71      0.71  4.8     0.14    NA  0.71
q1b      0.00      0.00    0.00      0.00  0.0     0.82    NA  0.00
q1c     -1.00     -1.00   -0.33     -0.33 -0.5     1.63    NA -0.33

 Item statistics 
    n raw.r std.r  r.cor r.drop mean   sd
q1a 6  0.35  0.34 -0.076  -0.19 0.50 0.55
q1b 6  0.71  0.71  0.673   0.24 0.50 0.55
q1c 6  0.88  0.88  0.867   0.61 0.67 0.52

Non missing response frequency for each item
       0    1 miss
q1a 0.50 0.50    0
q1b 0.50 0.50    0
q1c 0.33 0.67    0
Warning message:
In psych::alpha(df) :
  Some items were negatively correlated with the total scale and probably 
should be reversed.  
To do this, run the function again with the 'check.keys=TRUE' option
>

library(tibble)

res_tbl <- tribble(
    ~group, ~t_1, ~t_2, ~N,
    "A", 132, 480, 1200,
    "B", 154, 407, 1100,
    "C", 240, 528, 1200
)