Errors:  

- illustrate (should be 'illustrates')

- While, during different times of the day (awkward phrasing)

Corrected version:

The given line graph illustrates the transformation in radio and television audience in the UK for individuals above the age of 4 during different times of the day in 1992.

Improved version:

The provided line graph clearly depicts changes in radio and television audiences in the UK for individuals aged 4 and above during various time periods in 1992.

Errors:  

- ummistakeably (should be 'unmistakably')

- television was more dominant as compared to radio (awkward phrasing)

- while radio had a greater audience percentage in the morning hours (awkward phrasing)

Corrected version:

Overall, the data unmistakably indicates that television was more dominant than radio during evening hours, while radio had a greater audience percentage in the morning.

Improved version:

In summary, the data unequivocally reveals that television held greater sway than radio during evening hours, whereas radio enjoyed a larger audience share in the morning.

Errors:  

To begin with,

Corrected version:

To start, both radio and television had their lowest audience percentages around 4 am, with less than 5% of the UK population tuning in.

Improved version:

At 4 am, the audience for both radio and television was minimal, with less than 5% of the UK population engaged.

Errors:  

- Moreover, 

- commuting or prepare for the day (awkward phrasing)

Corrected version:

Furthermore, the radio audience then rose sharply to reach its maximum of around 25% at 8 am, while people listened to the morning shows or traffic updates while commuting or preparing for the day.

Improved version:

Subsequently, the radio audience experienced a sharp rise, reaching its zenith of approximately 25% at 8 am, as individuals tuned in to morning programs during their commute or daily preparations.

Errors: 

stayed low

Corrected version:

However, the television audience remained modest, with approximately 10% of the population watching TV.

Improved version:

In contrast, the television audience remained relatively small, comprising approximately 10% of the population.

Errors:  

Proceeding further, from noon onwards,

Corrected version:

Continuing, from noon onward, the radio audience gradually declined to approximately 15% at 4 pm, before a slight increase to 18% at 6 pm.

Improved version:

Subsequently, the radio audience exhibited a gradual decline from noon until 4 pm, reaching approximately 15%, followed by a slight uptick to 18% at 6 pm.

Errors:  

- Moreover

Corrected version:

Furthermore, the television audience showed a steady increase from noon to 8 pm, when it attained its peak of over 40%.

Improved version:

Additionally, the television viewership steadily increased from noon until 8 pm, reaching its pinnacle at over 40%.